164 Cards in this Set
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physiology
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study of biological functions
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tissue
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groups of similar cells and the intracellular molecules
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organs
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form of distinct shape and groups of tissues,two or more
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types of tissues:
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epithelial, connective, nervous, muscle
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epithelial tissue
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cover the body surface and line the body cavities, form the inner surface of hallow organs
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epithelial tissue classified by shape
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1. squamous: fishtail
2. cuboidal: cube
3. columnar: rectangle
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epithelial tissue classified by layering
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1. simple: one layer of cells
2. stratified: multiple
simple squamous is the most common type and usually lines capillaries and blood vessels; endothelium is an example of simple squamous
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connective tissue
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connects things, all used as supporting framework, lots of intracellular material so it contains gaps known as the matrix
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examples of connective tissue
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tendon: muscle to bone
ligament: bone to bone
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matrix
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composed of fibers on the ground substance, usually collagen or elastic
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ground substance
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dependent on whats connected, molecules and fibers that make up the matrix, loose connective gel like substance
example: bone has calcium, cartilage has chondrin
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types of connective tissue
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bone, cartilage, loose
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intracellular
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inside the cells
2/3 is water inside body
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intercellular
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outside the cells
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extracellular
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-everything outside the cells
-1/3 water in body
-part of fluid plasma is liquid part of blood
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interstitial fluid
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fluid between cells
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two other parts of extracellular matrix
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1. proteoglycans:part protein, part carb, mostly carb with protein chains
2. glycoproteins: bulk is protein, and carbs are bonded to the main protein
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solution
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solutes dissolved in solvent
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diffusion
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random molecular motion
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net diffusion
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concentration gradient (higher to lower)
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cell membrane is composed of…
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phospholipid bilayer: makes the inside of the bilayer hydrophobic (non polar) and is a barrier for a lot of things across the membrane
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what can cross the membrane
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1. small non polar molecules (oxygen, nitrogen, steroids)
2. small neutral molecules with polar covalent bonds (ethanol, CO2, urea) for respiration
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aquaporins
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how water molecules cross the membrane, channel molecules that are hallow proteins
-change permeability to H2O, can put porins in vesicle
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osmosis
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net diffusion of water across a semipermeable membrane
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how larger polar molecules cross the membrane
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(amino acids, glucose), need assistance from membrane carrier proteins
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how ions cross the membrane
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1. voltage gated channels: electrical voltage to open and close
2. mechanically gated proteins: channel proteins as a result of physical force
3. chemically gated channel proteins: chemical bond to open or close (ligand gated channels)
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ficks law
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Rate = [T x SA x (change in CG)]/
MW x D
describes rate of net diffusion, permeability
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4 ways body is modified to increase rate of net diffusion
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1. increase temperature
2. increase surface area
3. increase concentration gradient (circulatory sys is responsible)
4. minimize distance substance must diffuse & make membrane to diffuse over as thin as possible
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two requirements for osmosis two occur
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1. must be concentration gradient of solute
2. solute must be osmotically active
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osmotically active
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the membrane must be essentially impermeable to the solute in order to have osmosis
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osmotic pressure
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measure of the force required to stop osmosis; measured by the number of solute particles, not the nature
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what is osmotic pressure measured with? (TQ!)
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osmometer: glass tube 1/8 inch diameter, rubber band with dialysis bag attached filled with glucose in water, fluid inside bag will rise and where the fluid stops in the glass tube, the pressure of gravity equals the osmotic pressure
triple the solute concentration, triple the osmotic …
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osmolality
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total solute concentration of a solution
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how do you measure osmolality?
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freezing point depression
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isoosmotic
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solutions with the same osmolarity
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hyperosmotic
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relative term in the sense that we are comparing solutions in the terms of osmolality: has more
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hypoosmotic
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less osmolality, relative term
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tonicity
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affects the tone of the cell, tone meaning flaccid (lost water), turgid (gained water) or normal
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facilitated diffusion
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when a relativity large polar molecule (glucose, fructose, a.a.), goes into cell with the aid of a carrier protein, ATP is spent
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two properties that carrier show
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1. specificity
2. saturation
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carrier protein: specificity
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unique ligand binding site
- ligands bind to the ligand binding site and that triggers the carrier protein to change its conformation and its releases the ligand on the other side of the membrane (it can transport in either direction)
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carrier protein: saturation
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with facilitated diffusion, eventually the rate of transport increases until all transport proteins are occupied then the rate will flat line and can't increase anymore (saturated)
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active transport: 2 qualities
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1. all forms use ATP directly or indirectly, the cell must expend its own energy
2. they all move materials against the concentration gradient (substance going uphill, low to high concentration)
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two types of active transport
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1. primary active transport
2. secondary active transport
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primary active transport: how calcium pumps work
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1. ligand bonds to ligand bonding site, triggers hydrolysis of ATP which breaks down to ADP and Pi (exergonic = energy out)
2. adding Pi to the carrier protein changes its conformation (phosphorylation) which releases the ligand on the other side of the membrane
3. the release of the li…
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how do primary active transport pumps capture energy?
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when ATP is hydrolyzed, this energy is captured by forming a phosphorylated intermediate and the phosphate is covalently bonded to the pump (high energy - phosphate is highly electronegative)
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ATPases
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the primary active transport pumps are ATPases, meaning they have an enzyme with the ability to hydrolyze ATP
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primary active transport: Na+/K+ pump - how it works
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3 Na+ bind, ATP is hydrolyzed, pump is phosphorylated, then pump faces extracellular fluid to change the shape of the ligand binding site and 3 Na+ are ejected then 2 K+ bind to the ligand binding site which triggers dephosphorylation
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2 conformations of pumps
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phosphorylated and dephosphorylated
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what is an important role of the sodium potassium pump?
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create a membrane potential: source of PE which is used to perform work like power the secondary active transport
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what is resting membrane potential?
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-70 mV, inside is negative relative to the outside
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secondary active transport (co-, coupled)
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requires transport proteins (cotransport proteins) in the plasma membrane that couple the downhill moment of sodium with the uphill movement of something else
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what attracts sodium into the cell when a membrane is at rest?
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electrochemical gradient
-chemical: more Na out than in, diffuse down concentration gradient
-electrical: inside cell is negative with respect to outside, so its drawn to negative charge
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antiport
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when sodium and another molecule go opposite directions during transport (such as Na in cell down gradient and another molecule out against gradient)
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symport
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same direction transport (sodium and subtract carried across membrane in same direction)
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where does the energy come from for secondary transport and how is it used?
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ATP and it was spent using the Na+/K+ pump to make the gradient (this part is indirect use of ATP)
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how plants use secondary active transport
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proton ports:
-much more protons out of the cell than in
-uses electrical gradient that draws positively charged protons into the cell
-example: couple downhill movement of protons into cell using cotransport protein to uphill phosphate (symport)
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transport across epithelial membrane: 2 main concepts
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1. absorption of molecules into your body
2. reabsorption of molecules from urinary filtrate (in the kidney)
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characteristics of epithelial cells of the nephron and small intestine
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-they are the same
-columnar
-on the base of the cells are Na+/K+ pumps that use ATP and pump Na out and K in cell
-have cotransport proteins on apical surface (outer surface)
-glucose can leave by carrier protein or facilitative diffusion
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3 basic types of transport
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1. facilitative
2. secondary active (cotransport)
3. active transport
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Bulk transport
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for large substances like proteins, polysaccharides, cells used bulk transport to cross the cell membrane
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example of bulk transport
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pancreas has cells called isles of langerhans, inside are beta cells
-beta cells release insulin into the bloodstream in response to too much glucose in the blood
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2 types of bulk transport
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1. exocytosis: example - insulin is made in ER, packaged in vesicle (secretory vesicles), and they fuse with the plasma membrane then the protein is released to the outside of the cell
2. endocytosis: membrane folds inwards and pulls in some solution and the molecule then pinches off to …
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what is membrane potential the basis for?
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it is the basis for creating action potentials: how neurons (cells of the nervous system) and muscle cells can communicate
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two major ways that establish the membrane potential in animal cells
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1. Na+/K+ pumps
2. fixed anions in the cell membrane
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cytoplasm pH
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7.3 - slightly basic
- proteins and phosphates in the cytoplasm will have negative charge
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fixed anions
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fixed because they can't cross the membrane, anions because they are negatively charged
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why doesn't the negative interior of the cell attract cations from the outside such as Na+, Ca++, etc?
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the membrane is impermeable to most of these cations
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two ways for K+ to get in the cell
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1. K+ attracted to negative interior and can cross the membrane
2. Na/K pump - there are predominantly K ions in the cytoplasm
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equilibrium potential
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-the charge across the membrane that would exist if the membrane was only permeable to one kind of ion
-when the electrical gradient is exactly counteracted by the chemical gradient
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Nertz equation
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equilibrium potential =
61 mV / (Z log [X in]/[X out]
Z = valence
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resting membrane potential: due to two major properties
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1. concentration gradient of various ions involved
2. how permeable is the membrane to these ions
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cell signaling: direct with example
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gap junctions: 6 proteins called connexins that are arranged to make a channel and the interaction can go directly from one cell to another
example: cardiac muscle: how they all contract as a unit
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cell signaling: indirect
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release chemical (ligands)
-act on other cells
-3 forms of indirect signaling: 2 are local and 1 is long distance
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3 types of indirect cell signaling
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local: paracrine, synaptic
long distance: endocrine
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indirect cell signaling: local: paracrine
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the cells of an organ release a signaling molecule (can be a ligand, regulator, factor, etc), acts on other cells in the same organ which is why it is called local
example: nitric oxide is the factor in the endothelium of an artery that causes smooth muscle cells in the arteries to relax…
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synapse
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a junction between the neuron and another cell, the second cell may be another neuron or it might be an effector cell (a cell that response, does something, example: muscle cell that would contract, gland that would release a hormone in response to a stimulus)
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junction at a synapse: synaptic cleft: how indirect local synaptic cell signaling works
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at the cleft, the neuron releases the signaling molecule which is a neurotransmitter and the neurotransmitter diffuses across the cleft and binds to the neuron or the effector cell which causes them to do something
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indirect long distance cell signaling endocrine
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secretes a signaling molecule which is a hormone and released into the bloodstream and all cells can come in contact with it. however the hormone will only interact with target cells/organ because the target cells have a receptor that bond with the hormone
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in all cases of indirect cell signaling, what must the target cells have?
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receptors
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what are receptors
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proteins that can be part of the cell membrane or in the cytoplasm or nucleus
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genomic action
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if the receptors are in the cell (cytoplasm, nucleus), the signaling molecule will have a genomic action
-act on genes, make proteins, cause reaction, genes are turned on
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signal transduction pathways
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1. the receptor is on the plasma membrane & the signaling molecule bonds to the receptor
2. when it bonds that triggers the production of a 2nd messenger which can go into the cell & cause the cell to respond
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what is the first messenger in signal transduction pathways?
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the signaling molecule that bonded to the receptor on the membrane
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g proteins/g protein complex
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proteins that cause an interaction between a receptor and the plasma membrane and an effector protein which is also in the plasma membrane
-transmit information to the receptor in the plasma membrane
-interact with GTP (guanine instead of adenine)
-commonly seen in sensory systems
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g protein linked receptor
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NOTE: the g protein is not actually a receptor, this is
-on the extracellular surface: ligand binding site of receptor
-inside: interacts with g proteins
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what are the 3 parts of the g protein complex?
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3 proteins: alpha, beta and gamma
-beta/gamma: always joined together
-alpha: can separate, GTPase (can bind to GTP and can hydrolyze GTP into GDP and Pi)
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how the g protein works
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1. alpha is bonded to GDP
2. signaling molecule comes & bonds to g-linked receptor, makes alpha release GDP & bond GTP (turns on g-protein complex)
3. either the alpha subunit (still bonded to GTP) or the beta/gamma subunit travel across the membrane to the effector protein (can trigger…
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two basic components of the nervous system
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central nervous system and the peripheral nervous system
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central nervous system
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brain, spinal cord, like a switch board, central processor of a computer
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peripheral nervous system
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composed of cranial nerves (attached to brain), spinal nerves (attached to spine) and their branches
-like the wiring of a telephone system, the wires are conducting electrochemical impulses from one place to another
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2 basic types of cells in nervous system
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1. neurons
2. neuroglial cells (glial)
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neurons
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functional unit of the nervous system, can generate electrochemical impulses, not capable of mitosis
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neuroglial cells (glial)
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supporting the cells of the nervous system, capable of mitosis
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neuron: cell body
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large part of the neuron, where the nucleus is found and most of the cytoplasm
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neuron: nissl bodies
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described by early microscopists, dark appearing, rough ER, important site of protein synthesis in cells, very well developed in neurons so you can see them in microscopes
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neurons: processes (name 2 types)
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extension from cells body
1. dendrites
2. axons
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neurons: processes - dendrites
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very short, branch, very numerous, can generate graded potential (graded because they vary in size)
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neurons: processes - axons
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much longer than dendrites, can also branch, branches are typically called a collateral branches
-generate electrochemical impulses: AP
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axon hillock
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where the axon attaches to the cell body at an enlarged region
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nucleus/center
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ONLY IN CNS
cluster of neuron cells
example: in the brain stem there is a cardiac center (controls heart rate)
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ganglion/ganglia
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ONLY IN THE PNS
cluster of neuron cell bodies in the PNS
example: spinal nerve connected to spinal cord where dorsal root ganglion is connected
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nerve
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IN THE PNS ONLY
composed of a layer of connecting tissue, inside the tissue are many axons (similar to cutting open a wire), convey action potentials from one place to another
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tract
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ONLY IN CNS
bundles of axons, conveying AP from one place to another
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multipolar neurons
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many dendrites and one axon
example: motor neurons, association neurons
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pseudounipolar (unipolar) neuron
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one processes coming off the cell body, divides into a central branch and a long peripheral branch (main part of peripheral is like an axon and end acts like a dendrite)
-sensory information
-housed in dorsal root ganglion, central branch extends into spinal cord and peripheral branch c…
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chain of events in the dorsal root ganglion
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a somatic sensory neuron is hit and in the spinal cord there is an association neuron of the multipolar type which receives information and generates AP then a somatic motor neuron in the spinal cord sends out AP to calf muscle to move it (just an example of movement)
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bipolar neuron
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found in sensory epithelial, uncommon (olfactory, retina of the eye), one dendrite and one axon, don't generate AP, generate graded potentials so they "should be called dendrites"
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three functional types of neurons of the CNS
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motor, association, sensory
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motor neurons: CNS
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relay AP electrochemical impulses to effector glands (organs that respond or do something)
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association neurons: CNS
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involved with learning, memory, integration
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sensory neurons: CNS
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convey sensory information form peripheral of body to the CNS
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coelom
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all animals except sponges have a body cavity filled with mesoderm
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somatic component
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outer part of the body cavity
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visceral component
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inner part of the body cavity
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four functional types of neurons in the PNS
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1. somatic sensory
2. somatic motor
3. visceral sensory
4. visceral motor
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two types of PNS neuroglial cells
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satellite and schwann cells
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neuroglial cell: satellite cell in the PNS
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simple cuboidal in appearance, surround the cell bodies located in ganglia, provide correct ionic environment for cell bodies
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where would you find somatic and visceral sensory neurons?
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dorsal root ganglia
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schwann cells: neuroglial cells PNS
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important because they cover the axons of the PNS, form a neurilemma or neurilemmal sheath where these cells wrap around the axons of the PNS
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nodes of ranvier
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gaps between schwann cells, unmyelinated
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two basic functions of schwann cell sheath
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1. insulation: along the axons and the insulation helps the AP move more quickly and effectively
2. regeneration tube: if the axon is damaged they can form this to fix it
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what happens if the axon is damaged and a schwann cell is present?
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the axon will be phagocytized by the schwann cell and the schwann cell will form a regeneration tube to regrow it
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levels of insulation in schwann cells on PNS axons
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insulation: can have multiple wrappings around the axon or single
-myelinated or myelin sheath means multiple
-unmyelinated means one wrapping but still has neurilemma
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4 types of supporting cells of neurons in the CNS
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1. oligodendrocytes
2. microglial cells
3. ependymal cells
4. astrocyte
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oligodendrocyte: supporting cell of neuron in CNS
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-myelin sheath around axons but no neurilemma
-cant form regeneration tube
-reason why spinal cord gets permanently damaged
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microglial: supporting cell of neuron in CNS
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phagocytic properties
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ependymal cell: supporting cell of neuron in CNS
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in adults they line the cavities and canals of the CNS, have cilia on outer surface and circulate cerebrospinal fluid
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astrocyte: supporting cell of neuron in CNS
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1. foot like processes enclose the capillaries
2. recycle neurotransmitters
3. stimulate formation of blood brain barrier
4. control ionic environment around neurons
5. important in synapse formation, enclosed by astrocytes
6. take up glucose from blood, metabolize it into lactate th…
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grey and white matter
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grey: cell bodies and dendrites, not myelinated
white: composed of myelinated axons (tracts)
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what does it mean for neurons to be "irritable"?
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only muscle cells and neurons are irritable, they can alter their resting membrane potential to stimulation
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depolarization
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membrane potential becomes more positive
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repolarization
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potential goes back down to resting towards -70 mV
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hyperpolarization
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overshoots the resting membrane potential and goes past -70 mV, more negative but quickly returns back to -70 mV (decays)
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sodium voltage gated channel (voltage regulated)
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uses ball and chain mechanism, ONLY sodium flows through, channel opens in response to depolarization
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steps of sodium voltage gated channel
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1. closed; Na+ can't cross membrane
2. opened by depolarization of membrane then Na+ ions can flow through the channel
3. the membrane potential approaches equilibrium potential of Na+
4. only stays open ~ millisecond, then ball and chain mechanism deactivates it (no more flow of Na+ i…
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2 types of K+ channels
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1. leakage channels
2. K+ voltage gated channel
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K+ leakage channels
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always leak and open a little bit
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K+ voltage gated channels
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open in response to depolarization, respond to depolarization more slowly than Na+ VG channels do, a single depolarization will open K and Na VG channels but Na just opens first
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subthreshold
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no AP, not sufficient depolarization to trigger AP
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depolarization is an example of...
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positive feedback: opens Na+ gated channels, Na+ rushes into the cell and causes more depolarization which opens even more channels and causes even more depolarization
-only the ball and chain mechanism can stop it
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repolarization is an example of...
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negative feedback: inside of cell becomes more negative when K+ rushes out, causes less depolarization
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why are AP all or none?
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the threshold stimulus due to the positive feedback that opens all the Na+ gated channels, causes the max depolarization, all AP open ALL the Na+ gated channels
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how are AP modulated?
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frequency modulated: the greater the frequency, the greater the AP (per unit time), AP are not amplitude modulated because they are all the same amplitude, max frequency: you cannot generate another AP before the first one is finished
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two types of refractory periods
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absolute and relative
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absolute refractory period
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when all of the sodium VG channels are inactivated by the ball and chain mechanism, nothing can happen
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relative refractory period
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when the Na+ channels have returned to closed state, but only about half of them are closed and half are inactivated by the ball and chain mechanism - possible to generate another AP but stimulus of depolarization must be greater than normal
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why must the stimulus during the relative refractory period be greater than normal to generate an AP?
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1. K+ channels are still open and they are causing the membrane potential to become more negative due to K+ leaving cells - its becoming more negative and you want more positive
2. you must not only counter the K+ leaving the cells but overcome that to where you get cell depolarization
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cable properties of neurons
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description of the ability of the cytoplasm to conduct electrical charges
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how are electrical charges conducted through the cytoplasm?
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with decrement, cytoplasm is not a good conductor (high resistance and leakage of charges through the membrane)
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where are VG channels?
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none in membrane under the myelin sheath, if they are in the myelin sheath they are only at nodes of ranvier
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salutatory action
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AP potential at node then triggers AP to jump to next node, nodes must be less than 2mm apart
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types of synapse
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1. electrical: gap junctions
2. chemical
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chemical synapse
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a junction between a neuron and a second cell
-presynaptic cell: a neuron
-second cell: post synaptic cell
examples: neuromuscular junction, myoneural junction
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axodendritic synapse
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chemical synapse where post and presynaptic cells are neurons and forms synapse with a dendrite
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axosomatic synapse
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chemical synapse where post and presynaptic cells are neurons and forms synapse with cell body of neuron
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axoaxonic synapse
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chemical synapse where post and presynaptic cells are neurons and axon forms synapse with axon (uncommon)
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terminal boutons
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enlargement at tips of axon at presynaptic neuron in chemical synapse that are filled with neurotransmitters
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snare proteins (snare fusion complex)
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how the neurotransmitters are docked to the plasma membrane of the terminal boutons in chemical synapse
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exocytosis in chemical synapse
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plasma membrane of synaptic vesicle fuses with plasma membrane of terminal bouton and forms a pore and the transmitters are released through this pore
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CAMs
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how the synaptic cleft is stabilized in chemical synapses, cellular adhesion molecules, anchors the membranes of the terminal bouton and the post synaptic cell, maintains the synapse
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synaptotagmin
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sensor protein, calcium joins with this protein in the cytoplasm after diffusing down electrochemical gradient, when calcium bonds to this protein it causes a change in the structure of the snare fusion complex which triggers the exocytosis of the neurotransmitters
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EPSPs
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excitatory postsynaptic potential, creates AP, graded potentials which are depolarizations
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IPSPs
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inhibitory postsynaptic potential, graded potentials which are hyperpolarizations
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BIOL 460: Test 2