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BIOL 1108: Test 3
Eukaryotes
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a cell that has a distinct nucleus and other membrane-enclosed organelles
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Choaoflagellates
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protists that are the closest living relatives to animals
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Metazoans
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heterotrophs that ingest their food
multicellular
have true tissues: differentiated cells (including nervous and muscletissue)
lack cell walls
have structural proteins like collagen
95% animals are invertebrates (lack backbone)
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blastula development stage
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hollow sphere of cells formed during an early stage of embryonic development inanimals [1]. The blastula is created when the zygoteundergoes the cell division process known as cleavage.[2] The blastula is preceded by the morulaand is followed by the gastrula in the developmental sequence
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Protosome
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In which type of embryos does the endoderm originate from te mouth end, and if cells are removed, development is arrested
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Deuterostome
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the anus forms first
humans are deuterostomes
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Reproduction and Embryonic development in animals
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-Most animals reproduce sexually
-Diploid stage dominates the lifecycle
-After sperm fertilizes the egg, a diploid zygote is formed
-Zygote undergoes cleavage (early micotic cell division)
-A mulitcellular blastula is formed
-Blastula undergoes gastrulation which results in the formation of embryonic germ layers and a gastrula.
-- Most animals have a larva stage.
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Homeoboxes
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Sets of DNA sequences that regulate the expression of other genes
Hox genes in many animals
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Body plans
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1. Spherical symmetry
2. Radial Symmetry
3. Biradial Symmetry
4. Bilateral Symmetry
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Body plans: Radial vs. Bilateral Symmetry:
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Radial Symmetry- can be cut into four symmetrical parts.
Bilateral Symmetry- can only be cut into two symmetrical parts, down the center.
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dorsal
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back of body
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Ventral
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Bottom of animal
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anterior
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situated in the front
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Posterior
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back or facing behind/backwards.
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Cephalization
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the concentration of sensory neurons and interneurons in a head
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Germ Layers
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Ectoderm
Endoderm
Mesoderm
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coelom
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body cavity, fluid filled space seperatign the digestive tract from the outer body wall
cushions organs, hydrostatic skeleton, organs independent
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Homeostasis
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Maintenance of a relatively stable internal environment despite continuous outside changes.
A dynamic state of equilibrium.
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negative feedback/feedback inhibition
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one of the products downstream in a reaction series comes back and inhibits enzymatic activity in an earlier reaction
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In negative feedback loop,
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The response of the effector always results in decreasing the sensor aspect of the pathway and it counteracts the effectiveness of that pathway
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thermoregulation
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maintenance of internal temperature within a range that allows cells to function efficiently
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Radiation
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Emission of electromagnetic waves by all objects warmer than absolute zero. Radiation can transfer heat between objects that are not in direct contact.
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Evaporation
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Removal of heat from the surface of a liquid that is losing some of its molecules as gas.
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Convection
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Transfer of heat by the movement of air or liquid past a surface
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Conduction
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Direct transfer of thermal motion (heat) between molecules of objects in direct contact with each other
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insulation and sweating (adaptation- thermoregulation)
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epidrmis- outer skin covering
dermis- sweat gland, nerves, muscles
adipose- layer of fat for insulaiton
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nerve net
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A network of continuously interconnected nerve fibers (as contrasted with neural networks, in which fibers are connected by synapses)
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Nerve ring
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Nerves radiating evenly around the body.
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Central Nervous System (nervous system)
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Acts as control center for nervous system, issues orders to muscles glands and organs (BRAIN & SPINAL CORD)
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The nervous system: Peripheral nervous system
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The sensory and motor neurons that connect the central nervous system to the rest of the body. (brings info into CNS and carry out of the CNS)
- sensory receptors, muscles, and glands
Lie outside the brain and spinal chord
2 parts
somatic - voluntary muscles
automatic - involuntary (cardiac and smooth muscle)
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Parts of the Neuron
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Nucleus, cell body, dendrites, glial cells, axon, axon terminals, myelin sheath, nodes of ranvier, synaptic vesicles, neurotransmitters
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Dendrites
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Cytoplasmic extensions that receive information and transmit it towards the cell body.
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Axon
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long appendages where an action potential travels
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Myelin sheath
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A fatty material, made up of glial cells, that insulates the axon and allows for the rapid movement of electrical sheath. Where action potentials are transmitted.
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nodes of Ranvier
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increase efficiency of signal transmission
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membrane potential
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The electrical potential difference across a cell's plasma membrane. In membrane biophysics it is sometimes used interchangeably with cell potential, but is applicable to any lipid bilayer or membrane. Hence every organelle and every membranous compartment has a transmembrane potential.
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Resting potential
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-70mV
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why is the resting potential -70mV
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there is an unequal distribution of ions
membrane is more permeable to K+ ions than Na+
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Equilibrium Potential
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When the electrical gradient opposes the concentration gradient
Calculated using the Nernst Equation
Depends on the concentration gradient
E(k+)= -90mV and E(Na+)= +60mV
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2 factors influence membrane potential
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1)concentration gradient of ions
2)permeability of membrane(gated channels)
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Hyperpolarization
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1. a change in a cell's membrane potential that makes it more negative
2. After action potential membrane overshoots resting value (-70 mV)
3. As inside becomes more positive with accumulation of K + , the membrane becomes more negative than at resting potential and only gradually returns as extra K + ions diffuse away to equilibrium
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depolarization
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a shift in transmembrane potential toward 0mV. Involves sodium channels.
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The action potential generated at the axon
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hillock propagates as a wave along the axon.[59] The currents flowing inwards at a point on the axon during an action potential spread out along the axon, and depolarize the adjacent sections of its membrane. If sufficiently strong, this depolarization provokes a similar action potential at the neighboring membrane patches
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the refractory period of the axon is due to what?
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Na inactivation and K activation which hyperpolarizes the inside of the cell. Keeps the signal moving forward in the axon and doesn't allow it to move backward.
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Action Potential Propagation- Myelination
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myelinated axons transmit faster than unmyelinated axons. If depolarization shifts the membrane potential sufficiently, the result is a massive change in membrane voltage.
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Signal transmission between neurons
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neurons can receive more than one signal at a time; some are excitatory (depolarizing) [EPSP] and some are inhibitory (hyperpolarize) [IPSP]
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What are the 5 groups of neurotransmitters?
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-acytlcholine
-biogenic amines
-amino acids
-neuropeptides
-gases
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Acetylcholine
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Muscle stimulation, memory formation, learning
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Amino Acids
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long-term memory
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Biogenic Amines
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sleep, mood, attention, learning.
Used for nervous system disorders and treatments
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Neuropeptides
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pain reception
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Gases
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Nictric Oxide (local regulators)
Carbon Monoxide- hypothalmic hormone release; intestine smooth muscle plasma membrane hyper polarization)
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Post-Synaptic Responses
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Excitatory Post-Synaptic Potential (EPSP) and Inhibitory Post-Synaptic Potential (IPSP)
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Disorders of the nervous system
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Schizophrenia, depression, Alzheimer's disease, and Parkinson's disease
Genetic and environmental factors contribute to the diseases of the nervous system
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Sponges
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simple aquatic animals that lack tissues, feed as suspension feeders, with skeletons of organic matter or
calcium carbonate or silica secreted in the form of spicules, dating back to the Cambrian Period
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Vertebrates
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Animals with back bones
Linnaen classification, they are bilateral deuterostomes that belong to the kingdom animalia. (Deuterostomes are animals whose mouth develops after the ass)
Major sub-phylum of the phylum Cordata
Mobile organisims with sensory organs in a head bilateral symmetry, paired appendages.
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Lancelets
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-Marine suspension feeders
-Intermediate b/w vertebrates & invertebrates: notochord acts as endoskeleton in adults
-Feed by burrowing tail first in sediment; take in water through mouth and trap food on gill slits with the help of cilia
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Interstitial fluid
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fluid that surrounds body cells
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tissues
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collections of specialized cells and cell products that perform a relatively limited number of functions are called what?
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organs
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a group of several different kinds of tissues arranged so they can act together as a unit to perform a special function
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regulator
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internal mechanisms to control internal change in the face of external fluctuation
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Conformer
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animal uses for environmental variable if it allows its internal condition to change in accordance with external changes in the variable.
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set point
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maintaining a variable at or near this particular value
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Stimulus
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Environmental feature that provokes a response from an organism
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mechanisms of homeostasis
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- for a given variable, fluctuation above or below a set point serves as a stimulus - detected by a sensor and triggers a response
response returns the variable to set point
e.g. THERMOSTAT MODEL
moderate changes in the internal enviroment
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negative feedback
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a control mechanism that reduces or "damps" the stimulus
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positive feedback
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control mechanism that amplifies rather than reduces the stimulus.
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positive feedback loop
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do not play a major role in homeostasis, but instead help drive process to completion
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Endothermic
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describes chemical reactions that absorb heat energy from the surroundings
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ectothermic
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body heated by environment
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In negative feedback loop,
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a process whereby a change in an initial condition triggers a response that counteracts the initial change.
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integumentary system
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protective membrane, temperature regulator, and sensory receptor-- humans = convering of the body- skin, hair and nails
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countercurrent heat exchange
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transfer of heat between fluids that are flowing in opposite directions.
arteries and veins are adjacent to each other
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Cephalization
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the concentration of sensory neurons and interneurons in a head
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sensory neurons
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transmit information from eyes and other sensors that detect external stimuli
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Interneurons
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vast majority of neurons in brain. Form local circuits connecting neurons in the brain.
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Motor Neurons
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transmit signals to muscle cells and cause them to contract.
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Synapse
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tiny fluid filled gap between axon terminal of 1 neuron and the dendrite of another
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neurotransmitters
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chemical that causes activity in the neuron
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Glial Cells
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- supportive cells w/in the nervous tissue
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ion channels
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pores formed by clusters of specialized proteins that span the membrane. Allow diffusion
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Equalibrium potential
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the magnitude of the membrane voltage at equilibrium for a particular ion. When electrical gradient opposes the concentration gradient
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electrical force
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negative on the inside of the cell and positive on the outside.
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2 factors that influence membrane potential?
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1) the concentration gradient of different ions
2) the permeability of the membrane of those ions
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cambrain explosion
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-first radiation of animals with skeletons
-every animal phyla that exists now suddenly sppear 542 Ma
-first appearance of animals with hard parts
-defines base of phanerozoic
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ectoderm
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germ layer covering surface of embryo. Gives rise to outer layer covering of animal and central nervous system
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endoderm
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-innermost layer
-forms internal organs
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Diploblastic
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animal has ectoderm and endoderm
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Triploblastic
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- animals have an intervening mesoderm layer
- these include all bilaterians
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mesoderm
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gives rise to CT, muscle, BV's, lining of body cavities, lining of joint cavities
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Graded Potential
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Amount of change in potential is directly related to the intensity of the stimulus
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voltage-gated ion channels
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ion channels that open and close in response to change in membrane potential
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Chemical Synapse
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more common the electrical synapse
specialized for the release and reception of neurotransmitters and hormones
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Speed of propagation of action potential depends on:
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1) myelin
2) axon diameter
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excitatory post synaptic potential
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local depolarization of PSM that brings the neuron closer to the action potential thresholdd
-allows Na+ & K+ to pass simutaniously
-(-70mV)
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The nervous system: Peripheral nervous system
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The sensory and motor neurons that connect the central nervous system to the rest of the body. (brings info into CNS and carry out of the CNS)
- sensory receptors, muscles, and glands
Lie outside the brain and spinal chord
2 parts
somatic - voluntary muscles
automatic - involuntary (cardiac and smooth muscle)
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Schizophrenia
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- not about multiple personalitties, it is a psychotic disorder involving exteme delusions both physically and mentally
- low (e),(c), and (a)
-paranoid (hallucinations) disrogranized (scrambled speech) Catatonic (muscle spasms)
-dopamine released rapidly= symptoms
-blockage of glutamate receptors can induce strong symptoms
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Depression
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Items showing exteme pessimism & hopelessness.
major depressive disorder
bipolar disorder- mood swings from high to low
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Drug Addiction
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compulsive consumption of a drug and loss of control in limiting intake. The reward system of the brain provides motivation for activities that enhance survival and reproduction and addictive drugs use reward system= enhance dopamine pathway
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Alzheimers Disease
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dementia characterized my confusion or memory loss. Death of neurons in many parts of the brain. (Beta)-amyloid build up in plaques around neurons to cause death of surrounding neurons.
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Parkinson's disease
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A progressive neurological disorder that is characterized by tremor and weakness in the muscles and a shuffling gait. Death of neurons midbrain that normally release dopamine.
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Gastrovascular cavities
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-Are digestive compartments surrounded by cells
-Have only a single opening
- Cells remain moist on inside and outside of body to gain nutrients.
-Cells diffuse nutrients to other close surrounding cells
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Open Circulatory system
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bathes the organs directly and is not confined to vessels
--- Hemolymph
Advantages: chap to build and maintain
- no blood vessels
- no high pressure system
--ex: arthropods and most molluscs
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closed circulatory system
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blood is kept separate from the interstitial fluid
-blood is pumped through the vascular system by one or more hearts
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arteries
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Vessels that carry oxygenated blood away from the heart.
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Capillaries
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A network of microscopic blood vessels. They're the blood cell that must be squeezed through in single file. Their walls are thin and porous making it possible for gases, nutrients, and waste to transfer across walls rapidly.
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Veins:
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Blood vessels that carry blood from the tissues to the heart
Have all three tunics
Walls are thinner than arteries
Lumen larger
Media is poorly developed
65% blood flow
Pressure is low
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single circulation
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blood passes through the heart once in a complete circuit
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double circulation
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oxygen-poor and oxygen-rich blood are pumped separately from the right and left sides of the heart; maintains higher blood pressure
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Gas Exchange
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uptake of molecular O2 from the environment and the discharge of CO2 to the environment
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Countercurrent Exchange
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in which two fluids exchange substances while flowing in opposite directions. ex: fish gills
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tracheal system
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An respiratory system consisting of trachea, fine chitinous tubes in the body of an insect, conveying air directly to the tissues.
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