77 Cards in this Set
| Front | Back |
|---|---|
|
Sensory Receptors
|
detect stimulus
|
|
motor effectors
|
respond to stimulus
|
|
what does nervous system do?
|
links sensory receptors and motor effectors - consists of neurons and supporting cells
|
|
nerve
|
bundled group of axons that extend through body
|
|
sensory neurons
|
carry impulses to central
nervous system
|
|
Motor neurons
|
carry impulses from CNS
to effectors (muscles and glands)
|
|
Interneurons
|
provide reflexes and
associative functions (learning and
memory)
|
|
Dendrites
|
input - collect electric signals
|
|
Cell body
|
integrates incoming signals and generates outgoing signal to axon
|
|
axon
|
passes electrical signals to dendrites of another cell or to an effector cell
|
|
nerve singals
|
only flow one direction
|
|
Electrical Potential
|
exists when there is a separation of charged particles across some space
|
|
when a voltage exists
|
• Charged particles flow down their electrical gradient
• This flow is an electric current.
|
|
Resting potential
|
voltage (electrical charge difference) across neuron membranes at rest
|
|
electrochemical gradient
|
Concentration and charge differences across
membrane…tied to Na+ /K+ ATPase pump (energy used move these against their gradient
|
|
Resting neurons are most permeable
|
to K+ ions that follow their concentration gradient
|
|
Action Potentials
|
changes in membrane potential are the signals conducted by axons
|
|
4 Key points of Action potentials
|
1. Depolarization
2. Threshold Potential
3. An action potential is an all-or-none signal
4. All action potentials have the same magnitude
|
|
Depolarization
|
ion exchange across membrane so less polarized causes strong inward flow on Na+
|
|
Threshold potential
|
action potential will not occur unless depolarization great enough
|
|
when a neuron is at rest, a voltage is established because
|
membrane is selectively permeable to potassium
|
|
how to action potentials occur
|
because voltage-gated ion channels in axon membrane open or close in response to changes in voltage
|
|
Resting potential
|
voltage-gated Na+ channels closed
|
|
what opens with delay?
|
potassium channels
|
|
what opens voltage-gated channels
|
when the membrane is depolarized
|
|
Repolarization
|
strong outward flow of K+
|
|
why all-or-none
|
because Na+ channels more likely to open with depolarization
|
|
refractory
|
Na+ channels, once open & closed cant open for a short time,
|
|
why K+ channels open with a delay
|
re-establishes resting potential, would interfere with action potential
|
|
to make an action potential propagate faster
|
increase axon diamter = less resistance to current flow
prevent Na+ leaking except at discrete sites on the axon
|
|
Mechanoreceptors
|
respond to pressure (touch, hearing)
|
|
thermoreceptors
|
detect changes in temperature
|
|
pain receptors
|
sense harmful stimuli such as tissue injury
|
|
chemoreceptors
|
perceive specific molecules (smell, taste)
|
|
electromagnetic receptors
|
detect electric fields
|
|
photoreceptors
|
respond to particular wavelengths (vision)
|
|
chemical signals include
|
hormones
neurotransmitters
paracrine
pheromones
|
|
endocrine system
|
organs that secrete hormones into the bloodstream
|
|
hydrophilic hormones
|
cell surface receptor
binding triggers a signal transduction cascade within target cell
cellular response is altered protein function
|
|
lipophilic hormones
|
receptor inside cell
binding directly alters gene expression
cellular response is altered cell function
|
|
same hormone can trigger different responses in differing cells why ?
|
because of different receptors, secondary messengers, amplification steps, or active genes
|
|
hypothalamus-pituitary complex
|
releasing factors from hypo. stimulate pit. to secrete tropic hormones, targets glands, release regulatory hormones
|
|
cortisol is
|
lypophilic glucocorticoid
ensures availability of glucose for the brain
|
|
short and long term response to stress
|
epinephrine = short term
cortisol = long term
|
|
thyroid hormones
|
regulate amphibian metamorphosis
|
|
asexual reproduction
|
by mitosis
|
|
sexual reproduction
|
meiosis & gamete fusion
|
|
ultimate causation
|
addresses why a trait occurs, in terms of its effect on fitness
|
|
proximate causation
|
addresses how a trait is produced
|
|
acrosome
|
enzyme filled packet for digesting jelly layer
|
|
cortical granules
|
Ca2+ filled vesicles activated during fertilization
|
|
Oviparity
|
laying eggs; embryo develops in external environment
|
|
viviparity
|
live birth; embryos develop in mother's, rely on mother for food
|
|
ovoviviparity
|
embryos develop in mother's body, rely on yolk for food
|
|
puberty
|
GrRH
LH
FSH
testosterone or estradiol
|
|
Hormonal control of ovarian cycles
|
estradiol surges in follicular phase, progesterone in luteal phase
LH surge induces ovulation
Progesterone = maintains pregnancy
|
|
gestation
|
developmental period inside mother
|
|
amnion
|
a protective cushion of amniotic fluid
|
|
placenta
|
the primary conduit of nutrition and gas exchange for the growing fetus
|
|
umbilical cord
|
arteries transport blood from the circulatory system of the fetus to capillary bed in the placenta
|
|
three - tiered defense system of animals
|
barrier immunity (skin)
innate immunity (nonspecific)
adaptive immunity (specific; vertebrates only)
|
|
innate immunity
|
recognition of broad range of pathogens
few nonspecific receptors
rapid response
|
|
internal defenses
|
phagocytic cells
natural killer cells
antimicrobial proteins
inflammatory response
|
|
adaptive immunity
|
Vertebrates only
recognition of specific pathogens
broad set of receptors
slower response
|
|
Humoral response
|
antibodies defend against infection in body fluids
|
|
cell-mediated response
|
cytotoxic cells defend against infection in body cells
|
|
antigens
|
foreign molecules that the immune system recognizes as non-self
|
|
epitopes
|
antigen molecules specifically recognized by adaptive immune system
|
|
leukocytes
|
infection police - white blood cell, part of innate
|
|
mast cells
|
release histamine to increase blood flow to wounds
|
|
macrophages
|
release cytokines , coordinate fever and wound healing + ingest & kill pathogens
|
|
lymphocytes
|
natural killer cells
t cells
b cells
|
|
humoral immune response
|
antibodies from B cells help neutralize or eliminate toxins and pathogens in the blood and lymph
|
|
cell-mediated immune response
|
specialized Cytotoxic T cells destroy affected host cells
|
|
gene recombination
|
during lymphocyte maturation, takes place in each lymphocyte cell
|
|
clonal selection theory
|
each lymphocyte has 1000+ of unique receptors that recognizes only one antigen
lymphocyte activated when it binds
an activated lymphocyte divides and makes identical copies
some cloned cells live on in case infection recurs
|
|
allergies
|
exaggerated (hypersensitive) immune responses to antigens called allegens
|
BIOL 200B: CHAPTER 29