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Biology 310: Physiology > Physiology Final Exam > Flashcards

Physiology Final Exam Flashcards

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1
Q

what are the 4 basic cell/tissue types and their functions?

A

-muscle; skeletal, cardiac, and smooth: mechanical activity
-neurons/nervous: conduct electrical signals
-epithelial: secrete + absorption, protection
-connective: connect, anchor, support, ECM

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2
Q

__________ is the state of balance between physiological variables

A

homeostasis

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3
Q

a ___________ is when the increase or decrease of the variable being regulated brings about a response to move the variable in the opposite direction of the original change

A

negative feedback system

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4
Q

a __________ accelerates a process to get an “explosive” system

A

positive feedback system

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5
Q

in ___________, changes in variables are anticipated and prepared for to fine tune homeostatic response and minimize fluctuations in the regulated variable

A

feedforward regulation

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6
Q

what are the 4 intracellular chemical messengers and their functions?

A

-hormone: target cells in 1 or more distance places in the body
-neurotransmitters: neuron or effector cell in close proximity to site of neurotransmitter release
-paracrine: target cells in close proximity to site of release of the paracrine substance
-autocrine: acts on the same cell that secreted the substance

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7
Q

how does information flow in a neuron?

A

dendrite (receive info) -> cell body (genetic info for protein synthesis) -> axon hillock (propagate electrical signals) -> axon (carries ongoing signals to target cells) -> axon terminal (release neurotransmitters from axon)

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8
Q

what are the 3 functional classes of neurons and where to they send info to?

A

afferent: from receptors into the CNS
efferent: out of CNS to effector cells (muscles, glands, neurons, etc.)
interneurons: integrators and signal changers within the CNS

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9
Q

what are glial cells?
what are the 4 types?

A

surround the axon and dendrites of neurons and provide physical and metabolic support
nonneural
-oligodendrocytes: form myelin in CNS
-astrocytes: regulate composition of extracellular fluid in CNS by removing K+ and neurotransmitters
-microglia: macrophage-like immune function
-ependymal: line fluid filled cavities in brain and spinal cord and regulate flow of CSF

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10
Q

separation of charges results in __________

A

electrical potential

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11
Q

all body cells under resting conditions have potential difference across membranes so inside is __________ with respect to the outside

A

negative

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12
Q

membrane potential a result of 2 factors:

A

(1) uneven distribution of Na+ and K+ across plasma membrane
(2) unequal permeabilities of membrane to Na+ and K+

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13
Q

describe equilibrium potential and Nernst equation

A

2 fluxes become equal in magnitude but opposite in direction so there is no net movement of ions
the Nernst equation describes electrical potential needed to balance a given ion concentration gradient

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14
Q

the GHK equation is used to calculate ___________ by considering membrane permeabilities of other ions

A

resting membrane potential

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15
Q

what are leak channels?

A

constitutively open K+ channels
makes inside of cell negative

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16
Q

at resting membrane potential, driving force for Na+ diffusion is __________ than K+

A

greater

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17
Q

importance of the Na+/K+-ATPase pump?

A

maintains concentration gradients by creating a negative resting potential because 3 Na+ out and 2 K+ in every cycle
indirect contribution to membrane potential

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18
Q

what is a graded potential?

A

small changes in membrane potential confined to small regions of the plasma membrane
no threshold or refractory period

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19
Q

what is an action potential?

A

large alterations in membrane potential
generated rapidly, all-or-none

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20
Q

what are the 3 gated ion channels and how do they effect each other?

A

ligand gated: open in response to binding of signaling molecules
mechanically gated: open in response to physical deformation of plasma membranes
-> both mediate graded potentials to initiate stimulus for action potentials
voltage gated: give membrane ability to undergo action potentials

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21
Q

__________ are the myelin forming glial cells in the CNS
__________ are the myelin forming glial cells in the PNS

A

oligodendrocytes
Schwann cells

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22
Q

what is the difference between an excitatory and inhibitory synapse?

A

excitatory: depolarizes and brings the membrane potential in the postsynaptic cell closer to threshold
inhibitory: driven farther from threshold (hyper polarize) or stabilize at resting potential

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23
Q

compare electrical vs chemical synapses

A

electrical: plasma membranes of presynaptic and postsynaptic cells are joined by gap junctions to allow current to directly flow through connecting channels
chemical: axon of the presynaptic neurons end in axon terminals that hold synaptic vesicles that contain neurotransmitter molecules, permit integration of multiple signals

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24
Q

6 steps of neurotransmitter release

A

(1) action potential reaches terminal
(2) voltage gated Ca2+ channel opens
(3) Ca2+ enters axon terminal
(4) neurotransmitter released and diffuse into cleft
(5) neurotransmitter binds to post synaptic receptors
(6) neurotransmitter removed from synaptic cleft

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25
Q

compare EPSPs and IPSPs

A

EPSPs: net movement of positive ions into postsynaptic cell causing slight depolarization and bring membrane potential closer to threshold
IPSPs: potential change in postsynaptic neuron a byperpolarizng graded potential
- affect Cl- and K+ only

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26
Q

membrane potential of a __________ cell is affected by both excitatory and inhibitory inputs

A

postsynaptic

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27
Q

compare presynaptic inhibition vs facilitation

A

inhibition: decrease amount of neurotransmitter released
facilitation: increase amount of neurotransmitter released

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28
Q

what are the components of the CNS and PNS?

A

CNS:
brain
spinal cord

PNS:
afferent division (somatic sensory, visceral sensory, special sensory)
efferent division (somatic motor, autonomic motor - sympathetic, parasympathetic, enteric)

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29
Q

compare the afferent and efferent of PNS

A

afferent: info from sensory receptors to CNS
- long part of axon outside CNS and part in PNS

efferent: signals out of CNS to muscles, glands, and tissues
- somatic and autonomic

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30
Q

compare somatic vs autonomic nervous systems

A

both in PNS and efferent
somatic:
- single neuron between CNS and skeletal muscles cells
- innovates skeletal muscle cells
- lead only to muscle cell excitation

autonomic:
- 2 neuron chain connected by synapse between CNS and effector organ
- innervates smooth and cardiac muscle, glands, GI neurons, but not skeletal
- excitatory and inhibitory

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31
Q

compare sympathetic vs parasympathetic neurons

A

sympathetic:
- from thoracic and lumbar regions of spinal cord
- ganglia lie close to spinal cord to form 2 chains on each side of cord - sympathetic trunk

parasympathetic:
- from brainstem and sacral portion of spinal cord
- ganglia lie within or close to organs postganglionic neurons innervate

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32
Q

3 protective elements of the brain

A

meninges: thick dura mater next to bone, arachnoid mater in the middle, and thin pia mater next to nervous tissue

cerebrospinal fluid: between arachnoid and pia

blood brain barrier: controls substances that enter extracellular fluid of the brain and rates at which they enter

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33
Q

5 types of sensory receptors and what they detect

A
  • mechanoreceptors: pressure, stretch, touch, blood pressure, tension
  • thermoreceptors: cold or warmth
  • photoreceptors: light wavelengths
  • chemoreceptors: binding of particular chemicals to receptor membrane
  • nociceptors: pain
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34
Q

transduction of a given stimulus leads to a graded potential in receptor membrane called the ___________

A

receptor potential

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35
Q

compare slowly vs rapidly adapting receptors

A

slowly: maintain persistent or slowly decaying receptor potential during a constant stimulus, initiating an action potential in afferent neurons for duration of stimulus

rapidly: generate receptor potential and action potentials at onset of stimulus but quickly stop responding

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36
Q

define coding, sensory unit, and receptive field

A

coding: conversion of stimulus energy to a signal that conveys relevant sensory information to CNS

sensory unit: a single afferent neuron with all receptor endings

receptive field: area of body that leads to activity in a particular afferent neuron when stimulated

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37
Q

stimulus modality primarily coded for by __________

A

type of receptors activated

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38
Q

__________ along afferent neurons and ___________ are 2 ways in which stimulus intensity is coded

A

frequency of 2 action potentials
recruitment of sensory units

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39
Q

what is lateral inhibition?

A

information from afferent neurons with receptors at edge of stimulus is strongly inhibited compared to information from afferent neurons at the center

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40
Q

6 factors that affect perception

A
  • sensory receptor mechanisms and processing info along efferent pathways
  • emotions, personality, experience
  • lack of suitable receptors
  • damaged neural networks
  • drugs
  • mental illness
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41
Q

4 modalities for somatic sensation and the receptors for them

A

touch and pressure: mechanoreceptors
posture and movement: muscle-spindle stretch receptors and Golgi tendon organs
temperature: thermoreceptors
pain and itch: nociceptors

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42
Q

compare referred pain and hyperalgesia

A

referred pain: sensation of pain experienced at site other than injured or diseased tissue
hyperalgesia: increased sensitivity to pain stimulus

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43
Q

what is analgesia?

A

selective suppression of pain without effects on consciousness or other sensations

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44
Q

specific pathways for somatic senses cross from the side of the body where __________ to the other side in the spinal cord or brainstem

A

receptor is located

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45
Q

compare the anterolateral pathway and the dorsal column pathway

A

anterolateral: ascending, makes its first synapse between sensory receptor neuron and second neuron located in gray matter of the spinal cord

dorsal column: sensory neurons do not cross over or synapse immediately, instead ascend on same side of cord and make its first synapse in the brainstem

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46
Q

what is accommodation?
what is the problem with someone who can’t see distant and near?

A

accommodation: shape of lense is altered by contraction and relaxation of ciliary muscle

viewing distant: eyeball too long or refraction too great

viewing near: eye too short for lens, images focused behind the retina

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47
Q

compare hyperopia to myopia

A

myopia: unable to see distant objects (nearsighted)

hyperopia: poor near sight, can be seen if accommodation reflex increases the curvature of the lens (farsighted)

48
Q

2 types of photoreceptors

A

rods and cones

49
Q

compare rods and cones

A

rods: disc membranes are intracellular
- extremely sensitive and respond to very low levels of illumination

cones: light sensitive discs formed from in-foldings of the surface plasma membrane
- only respond to bright light

50
Q

all rods and cones face __________ and light must travel through ___________ before reaching photoreceptors

A

the back of the retina
all retinal cells

51
Q

ON vs OFF pathways

A
52
Q

compare dark vs light adaptation

A

dark: bright into dark light
- “temporary blindness”
- rhodopsin cannot respond fully again until restored to resting state by enzymatic reassociation of retina with opsin, which takes several minutes

light: dark to bright light
- rhodopsin activated as retinal dissociates
- cones operating

53
Q

___________ whose axons form the optic nerve are the afferent neurons in the visual system

A

ganglion cells

54
Q

sound waves are caused by vibrations of molecules and have the properties of __________ and __________

A

frequency and pitch

55
Q

what is the pathway of a sound wave?

A

external auditory ear canal -> tympanic membrane -> middle ear -> inner ear -> malleus, incus, stapes -> oval window

56
Q

what are the semicircular canals?

A

when the head moves, semicircular canals and attached body of hair cells move with it
the direction of head movement determines the direction stereo cilia are bent and which hair cells are stimulated

57
Q

all receptors in vestibular system are _____receptors

A

mechano

58
Q

what are the 5 taste submodalities and what is detected to produce it?

A

sweet: glucose
sour: acid
salty: sodium
bitter: G protein mediated
unami: glutamate and amino acids

59
Q

the olfactory system is unique in that its neurons do not synapse in the thalamus but instead _____________

A

project directly to olfactory cortex and limbic system

60
Q

a contraction is the generation of __________, not just muscle shortening

A

tension

61
Q

what is a motor unit?

A

a motor neuron and the muscle fibers it innervates
located in one muscle but are distributed throughout
contract when an action potential occurs in a motor neuron

62
Q

9 steps that occur at the neuromuscular junction

A

1) motor neuron action potential
2) Ca2+ enters voltage-gated channels
3) acetylcholine release
4) acetylcholine binding opens ion channels
5) Na+ entry
6) local current between depolarized end plate and adjacent muscle plasma membrane
7) muscle fiber action potential initiation
8) propagated action potential in muscle plasma membrane
9) acetylcholine degradation

63
Q

6 steps of excitation-contraction coupling?

A

1) action potential propagated along muscle cell membrane and into T-tubules
2) Ca2+ released from terminal cisternae
3) Ca2+ binding to troponin removes blocking action of tropomyosin
4) cross-bridge binds, rotates, and generate force
5) Ca2+ transported back into sarcoplasmic reticulum
6) Ca2+ removal from troponin restores tropomyosin blocking action

64
Q

what is the sliding filament mechanism?

A

force generation produces shortening of skeletal muscle fiber and the overlapping thick and thin filaments in each sarcomere move past each other, propelled by movements of cross-bridge

65
Q

4 steps of the cross-bridge cycle

A

1) cross-bridge binds to actin
2) cross-bridge moves
3) ATP binds to myosin, causing cross-bridge to detach
4) hydrolysis of ATP energizes cross-bridge

66
Q

4 functions of ATP in skeletal muscle

A

1) hydrolysis of ATP by Na+/K+-ATPase in plasma membrane maintains Na+ and K+ gradients
2) hydrolysis of ATP by Ca2+-ATPase in sarcoplasmic reticulum provides the energy for active transport of calcium ions reticulum
3) hydrolysis of ATP by myosin-ATPase energizes cross-bridges, providing energy for force generation
4) binding of ATP to myosin dissociates cross-bridges bound to actin, allowing the bridges to repeat their cycle of activity

67
Q

compare isometric vs isotonic contractions

A

isometric: muscle develops tension but does not shorten; when muscle supports a load in a constant position or attempts to move another load that is greater than the tension
isotonic: muscle changes length while load on muscle remains constant
- 2 types:
- concentric: tension exceeds load and shortening occurs
- eccentric: unsupported loads is greater than the tension generated by cross-bridges

68
Q

3 types of skeletal muscle fibers

A

slow-oxidative: combine low myosin-ATPase activity with high oxidative capacity
fast-oxidative-glycolytic: combine high myosin-ATP activity with high oxidative capacity and intermediate glycolytic capacity
fast-glycolytic: combine high myosin-ATPase activity with high glycolytic capacity

69
Q

a whole muscle is made up of a combination of different types of muscle fibers organized into __________

A

motor units

70
Q

tension can be developed in a whole muscle depends upon 2 factors:

A

(1) tension developed by each individual fiber
(2) number of active fibers

71
Q

what are muscle antagonists?

A

groups of muscles that produce oppositely directed movement at a joint

72
Q

compare and contrast structure of smooth and skeletal muscle

A

smooth: not striated
not under direct voluntary control
smaller cells
smaller concentration of thick myosin containing filaments and thin actin containing filaments

skeletal:
striated
under voluntary control
larger cells
larger concentration of thick myosin containing filaments and thin actin containing filaments

both:
use cross-bridge movements between actin and myosin to generate force
calcium ions generate force
contain thick myosin containing filaments and thin actin containing filaments

73
Q

cross-bridge activation in smooth muscle (5 steps)

A

(1) Ca2+ binds to calmodulin, a Ca2+-binding protein that is present in the systole of all cells and whose structure is related to troponin
(2) Na2+-calmodulin complex binds to another systolic protein, myosin-light chain kinase, thereby activating enzyme
(3) active myosin, light-chain kinase then uses ATP to phosphorylate myosin light chain in globular head of myosin
(4) phosphorylation of myosin drives cross-bridge away from thick filament backbone, allowing it to bind to actin
(5) cross-bridges go through repeated cycles of force generation as long as myosin light chains are phosphorylated

74
Q

2 sources of Ca2+ to initiate contraction in smooth muscle

A

(1) sarcoplasmic reticulum
(2) extracellular Ca2+ entering cell through plasma membrane Ca2+ channels

75
Q

what is the latch state?

A

in smooth muscle when stimulation is persistent and cytosolic Ca2+ concentration remains elevated, the rate of ATP hydrolysis by the cross-bridge decline even though isometric tension is maintained

76
Q

what is the pacemaker potential?

A

following depolarization, the membrane begins to depolarize so a series of action potentials occurs, producing a rhythmic state of contractile activity

77
Q

___________ muscle can be excited or inhibited by neural activity and __________ muscle can only be excited

A

smooth
skeletal

78
Q

compare single vs multiunit smooth muscle

A

single:
-undergo synchronous activity, both electrical and mechanical-whole muscle tissue responds to stimulation as a single unit
-in intestinal tract, uterus, and small blood vessels

multi:
-no or few gap junctions
-each cell responds independently and tissue behaves as multiple units
-in large airways to lungs, large arteries, hair in skin

79
Q

10 steps of excitation-contraction coupling

A

(1) membrane depolarized by Na+ entry as an action potential begins
(2) depolarization opens L-type Ca2+ channels in T-tubules
(3) small amount of “trigger” Ca2+ enters cytosol, contributing to cell depolarization
(4) trigger Ca2+ binds to and opens ryanodine receptor Ca2+ channels in the sarcoplasmic reticulum membrane
(5) Ca2+ flows into cytosol, increasing Ca2+ concentration
(6) binding of Ca2+ to troponin exposes cross-bridge binding sites on thin filaments
(7) cross-bridge cycling causes force generation and sliding of thick and thin filaments
(8) Ca2+-ATPase pumps return Ca2+ to sarcoplasmic reticulum
(9) Ca2+-ATPase pumps and Na+/Ca2+ exchangers remove Ca2+ from cell
(10) the membrane is repolarized when K+ exes to end action potential

80
Q

the strength of a contraction can be varied by __________ or __________

A

neurotransmitters
hormones

81
Q

what are L-type Ca2+ channels?

A

causes depolarization during cardiac muscle cell action potentials due to the influx of Ca2+ through voltage-gated channels

82
Q

interneurons receive sensory information from (3):

A

(1) same muscle that is controlled by motor neuron
(2) other nearby muscles
(3) neurons in the tendons, joints, and skin

83
Q

all muscle spindle stretch receptors provide sensory information about the overall __________ and rate of ___________

A

length of the muscle
length change

84
Q

what is alpha-gamma coactivation?

A

prevents loss of information about muscle length during rapid shortening contractions

85
Q

what is the monosynaptic stretch reflex?

A

afferent nerve fibers in stretched muscle synapse directly on motor neurons to that muscle without any interneurons

86
Q

compare reciprocal innervation and synergistic muscle activation

A

reciprocal innveration:
- divergence of neuronal pathways to influence both agonist and antagonist muscles of a particular movement
- simultaneously contracted to stiffen a limb joint
- branches of afferent nerve endings from stretch receptors end on inhibitory interneurons

synergistic muscle activation:
- muscles whose contractions assist the intended motion

87
Q

___________ provide sensory information about the tension being generated by a muscle

A

Golgi tendon organs

88
Q

withdrawal reflex

A
89
Q

function of the basal nuclei

A

form a link in the looping of parallel circuits in which activity of motor system is transmitted from a specific region of sensorimotor cortex to basal nuclei, to thalamus, and back to cortical area

90
Q

define muscle tone and hypertonia and hypotonia

A

muscle tone: when skeletal muscle is relaxed there is a slight and uniform resistance when stretched by an external force
-hypertonia: abnormally high muscle tone
-hypotonia: abnormally low muscle tone

91
Q

postural reflex

A
92
Q

3 chemical classes of hormones

A

amines
peptides and proteins
steroids

93
Q

the amino acid _________ is the precursor to all amine hormones

A

tyrosine

94
Q

___________ is precursor to all steroid hormones

A

cholesterol

95
Q

__________ is the predominant steroid secreted by the testes and is converted to the other hormones in target cells

A

testosterone

96
Q

only a _________ hormone is able to diffuse out of the capillaries and exert effects on target cells

A

free

97
Q

contraction of a hormone in the blood is determined by __________ and rate of __________

A

hormone synthesis/secretion
hormone removal/metabolism

98
Q

compare up and down regulation

A

up: an increase in the number of hormones receptors in a cell
down: a decrease in receptor number

99
Q

what is a tropic hormone

A

stimulates secretion of another hormone and growth of stimulated gland

100
Q

what does tropic and trophic mean?

A

tropic: stimulates secretion of another hormone and growth of stimulated gland
trophic: specifically referring to growth-promoting actions

101
Q

define primary and secondary hypo- and hyper- secretion of hormones

A

primary hypo: secreting too little hormone the gland is not functioning properly
secondary hypo: endocrine gland receiving too little stimulation by its tropic hormone

primary hyper: gland secreting too much of the hormone on its own
secondary hyper: excessive stimulation of gland by its tropic hormone

102
Q

define hypo- and hyper-responsiveness

A

hypo: decreased responsiveness of target cells to hormone
hyper: increased responsiveness of target cells to hormone

103
Q

2 posterior pituitary hormones

A

oxytocin and vasopressin

104
Q

__________ hormones are first in a 3-hormone sequence to bring about desired response

A

hypophysiotropic

105
Q

compare T4 and T3

A

T4:
- 4 iodines
- converted to T3 in target tissues by enzymes

T3:
- 3 iodines
- major thyroid hormone

106
Q

__________ thyroid hormone concentrations exhibit negative feedback control on hypothalamus and anterior pituitary gland

A

plasma

107
Q

__________ hormone receptors are found in nuclei of most cells of body

A

thyroid

108
Q

what is hypothyroidism?

A

plasma concentrations of thyroid hormone below normal

109
Q

describe the process of fertilization

A

The spermatozoon and ovum combine their haploid nuclei to create a diploid zygote.
Once a male ejaculates, the spermatozoa increase motility and fertilize the ovum.
A second oocyte is released from the ovary and moves along the uterine tube, and the spermatozoa passes through the corona radiata to reach the cell membrane of the oocyte. The spermatozoa release an enzyme, hyaluronidase, that allows it to enter the oocyte.
The oocyte goes through meiosis while the spermatozoon creates chromosomes to combine with the maternal chromosomes.

110
Q

why are so many sperm needed for successful fertilization?

A

The male needs to ejaculate around 300 million spermatozoa because most of them do not survive the journey through the vagina and to the uterus, only about 100 of them do, and only a single ovum is released from an ovary during ovulation.
Therefore, more sperm needs to be released to increase the chances of fertilization since only one egg is produced.

111
Q

how are the 3 germ layers formed?

A

Within a few days of implantation, cells begin the process of gastrulation where the cells of the epiblast move to the primitive streak, where invagination occurs.
Cells are sent into the region between the epiblast and the hypoblast.
The epiblast forms the ectoderm, the hypoblast forms of the endoderm, and the cells that proliferate between those 2 layers forms the mesoderm.

112
Q

describe the structure of a blastocyst

A

A solid ball of cells, the morula, enters the uterus and changes into a blastocyst, which is a hollow ball of cells with a cavity called the blastocoele.
There are cells outside, trophoblasts, and the cells inside form the inner cell mass

113
Q

what are the functions of the 4 extraembryonic membranes?

A

The yolk sac at first has a large role in providing the embryo nourishment but this later decreases when the amnion begins to form. The amnion provides protection by lining the amniotic cavity and envelops the embryo in amniotic fluid.
The allantois forms part of the urinary bladder and contributes to the body stalk which is the protective tissue between the embryo and the chorion.
The chorion encases the embryo and extend villi and blood vessels to eventually establish the structure and development of the placenta.

114
Q

how does a fetal obtain nutrients and gases from the maternal blood

A

A fetus obtains nutrients and gases from the maternal blood through the placenta.
The placenta is connected to the fetus via the body stalk, which combines with the yolk stalk to form the umbilical cord.
The umbilical cord has 2 arteries that transport deoxygenated blood to the placenta and a single vein that returns oxygenated blood to the embryo.

115
Q

from what structures do the 4 major tissue groups arise?

A

The ectoderm forms the nervous system, skin, hair, and nails, which contributes to the rise of nervous tissue and epithelial tissue.
The mesoderm forms the skeletal and muscular systems, which contributes to the rise of muscular tissue and most connective tissues. The endoderm forms the linings of the respiratory and digestive systems, where epithelial tissues can also arise from.

Biology 310: Physiology (1 decks)

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