term1 Flashcards
1
Q
what is homeostasis?
A
maintaining stable internal conditions regardless of external factors
2
Q
what is included in the internal environment?
A
fluid surrounding cells, interstitial fluid, blood plasma etc
3
Q
what is included in the external environment?
A
region outside body. but also included respiratory, digestive, and urogenital tract as they interact w/ outside factors
4
Q
what feedback loop is mainly used in homeostasis?
A
negative feedback loop
5
Q
how does a negative feedback loop go?
A
set point -> control center -> effector -> controlled variable -> sensor. would keep going till it reached desired point.
6
Q
how does a positive feedback loop go?
A
set point -> control center -> effector -> controlled variable -> sensor. would keep going.
7
Q
feedback loops in the body rely on these two systems…?
A
nervous and endocrine system
8
Q
in the body, the control center of a feedback loop is?
A
hypothalamus, it activates the effectors - organs
9
Q
to decrease temperature in the body, what would the control center tell the effectors to do?
A
shiver and increase blood flow to skin
10
Q
to decrease temperature in the body, what would the control center tell the effectors to do?
A
dilate skin and sweat glands to sweat
11
Q
what keeps the ionic concentration differences between the intracellular and extracellular fluids?
A
selective permeability of the plasma membrane
12
Q
The events of an action potential…
A
Strong depolarization at the axon hillock triggers the opening of voltage-gated Na+ channels. Na+ rushes into the neuron, down its concentration gradient. The nerve membrane depolarizes to +35 mV. Voltage-gated Na+ channels become inactivated and voltage-gated K+ channels open. K+ rushes out of the cell down its electrochemical gradient. The efflux of K+ hyperpolarizes the cell to -90 mV. K+ channels close and the resting membrane potential returns to -70 mV by leakage of ions through channels.
13
Q
During the actin-myosin-ATP cycle, ATP binds to the myosin head causing:
A
the myosin head to detach from actin
14
Q
f oligodendrocytes were destroyed by a virus, what would occur?
A
saltatory conduction would be lost in the central nervous system.
15
Q
If the medulla were damaged, what would occur?
A
the person would have trouble with involuntary functions, such as breathing.
16
Q
what allows the functioning of organs?
A
when homeostasis controls the volume of fluid on concentration of ions
17
Q
what are the body fluid compartments?
A
intracellular is inside the cells. extracellular outside cells. extracellular split into interstitial and plasma.
18
Q
what are the percentages of the body fluid compartments?
A
intracellular takes up 67. interstitial takes up 26.4 and plasma is 6.6
19
Q
In a diagram of two cells and a nearby capillary, where would the intracellular fluid, the interstitial fluid, and plasma be?
A
the cells would be intracellular, interstitial is the area surrounding the cell, and intracellular would be the capillary (blood supply)
20
Q
what has higher concentrations inside the cell? and higher outside?
A
potassium and proteins are high inside a cell. and outside the cell, sodium, chlorine, and calcium are high
21
Q
how does the cell membrane regulate what passes thru?
A
channels, pores, and special transport systems
22
Q
in the phospholipid bilayer, what faces the water interior/exterior? what does the composition of this allow for?
A
the phosphate head faces the water while the fatty acid tail is directed inside. bc the fatty acids are hydrophobic this allows for the prevention of water and water soluble molecules passing thru.
23
Q
in a phospholipid, what part is hydrophobic and hyrdophillic?
A
the phosphate head is hydrophilic while the fatty acid tail is hydrophobic
24
Q
where in the phospholipid bilayer are carbohydrates, cholesterol, and membrane proteins? and what do they do excluding proteins?
A
carbohydrates are found outside the membrane, it can help with cell recognition and protection for plasma membrane. cholesterol can be found inside and ensures membrane remains fluid and flexible and prevents the tails from touching.
25
what are the 5 functions of membrane proteins?
receptors for chemical hormones and NTs. enzymes speed chemical reactions and molecule breakdown. ion channels/pores allow water-soluble substances into cell. membrane transport carrier transports molecules across the membrane. cell identity markers such as antigens help distinguish between normal cells and foreign particles.
26
what are the major ways substances cross the membrane?
endocytosis/exocytosis and pinocytosis. these are bulk transport and active transport bc they require energy. there is diffusion thru the lipid bilayer for fat soluble molecules and diffusion thru protein channels for water soluble. and facilitated diffusion
27
what is diffusion?
going from high to low concentration down the gradient due to molecules random thermal motion
28
what is the electron gradient? electrochemical equilibrium?
oppositely charged molecules move down gradient towards eachother. if concentration gradient and electron gradient are in balance and in opposite directions there is no ion movement reaching electrochemical equilibrium is reached
29
what are the four factors affecting diffusion?
size of protein channels limits size of molecules. the charge on molecules prevent some from going thru channels with the same charge on their proteins. a greater electrochemical gradient increases the rate of diffusion as opposite charges attract. and the number of channels in membrane bc more channels means an increased rate
30
what is facilitated diffusion and how does it differ from simple diffusion?
it is for water substances which are too large to pass thru protein channels such as sugar. they will travel across by attaching to protein carriers on the membrane. this doesnt require energy. it differs from simple diffusion bc it is dependent on the number of available proteins.. when all carriers are in use the system becomes saturated and cant operate faster .. it is limited
31
what is active transport and how does it differ from facilitated diffusion? hows it similar?
unlike chemical diffusion it uses energy bc molecules are moving up the concentration gradient. like facilitated diffusion, can be saturated and display chemical specificity and competitive inhibition.
32
what is chemical specificity? what could it lead to?
carrier protein will only interact with specifically shaped molecules. this could lead to competitive inhibition by molecules with similar shapes.
33
what is osmosis?
when theres a difference in concentration of water across membrane, a net movement of water down concentration occurs. water requires special pores bc it cant diffuse thru lipid membranes
34
what factors affect diffusion?
permeability of membrane to solutes, concentration gradient of solutes, and pressure gradient across the membrane
35
what are osmoles?
osmole is the number of active particles (e.g. Na, Cl, K)in solution which causes osmosis.
36
what are isotonic, hypotonic, and hypertonic solutions? what would happen to a cell that is hypotonic/hypertonic?
isotonic is when the concentration is similar to body fluids. hypotonic is when it has lower concentration which would cause osmosis into the cell and to swell. hypertonic is when it has higher concentration and cause osmosis out the cell and the cell would shrink.
37
what is body fluid concentration in a human?
300 mOsmoles/kg of water
38
what is resting membrane potential? what happens to ions during this?
electrical potential difference across the membrane in resting cells. it is -70mV bc it is negative compared to the outside. potassium ions try to leave the cell and sodium tries to enter
39
what are the two functions of the sodium potassium pump?
maintains concentration gradient of the two ions as they try to leak in/out. prevents swelling ... the pump reduces the amount of particles inside (3 out and 2 in)
40
what does the sodium potassium pump pump in and out?
3 sodium ions out and 2 potassium ions in. it goes against the gradient.
41
what are excitable cells?
they use RMP to generate action potential which allows nerve cells to communicate and muscles to contract
42
what do dendrites do?
they increase the surface area of the neuron and receives signals.
43
what does the terminal bouton do?
swelling at the ends contains mitochondria and other vesicles. the chemicals inside the allow transmission from synapses into target cell
44
what are voltage dependent sodium and potassium channels? when do they open?
voltage gates channels are found on the axons and are essential for the generation of ATP. they open when the inside of the cell becomes more positive aka depolarization
45
what are the voltage levels of depolarization?
from -70mV to 35mV
46
what are the voltage levels of repolarization?
from 35mV to -70mV
47
what are the voltage levels of hyperpolarization?
from -70mV to -90mV
48
when does the permeability for sodium ions and potassium ions peak?
for sodium it peaks at around around 35mV. for potassium it is after sodium's, it is after when the sodium gates start to close. since potassium gates close slowly the permeability lasts longer than sodium's
49
what are the steps of an action potential?
strong depolarization at axon hillock opens most sodium VGCs. sodium goes down electrochemical gradient into the neuron and the membrane quickly depolarizes to 35mV. sodium channel inactivates as potassium channel begins to open. potassium goes down electrochemical gradient out the cell and the membrane repolarizes from 35mV to -70mV. because potassium gate closes slowly, more potassium leaves cell causing it to hyperpolarize to -90mV. Gate closes and membrane potential slowly returns to -70mV.
50
what is the threshold for action potential?
to launch an action potential the sodium depolarizing force must be stronger than potassium leaving and chlorine entering the cell because they repolarize. the depolarizing force must be strong to open the sodium voltage gated channels.
51
what is overshoot in action potential?
sometimes occur at the peak of depolarization. it has high permeability to sodium and close to the equilibrium potential of sodium which is 55mV
52
what direction does the action potential travel? in relation to the cell
from the cell body to the axon terminal
53
how does the action potential propagate down membrane of an excitable cell? how is it different in a myelinated cell?
ionic currents inside and outside axon are carried by positively charged ions. the current goes from positive areas to negative areas. it depolarizes areas and opens VGCs to move to next area and the process repeats. in a myelinated cell it will only occur at the nodes of ranvier.
54
what is saltatory conduction? and how is it more convenient?
action potential propagation in myelinated cells. VGCs only exist at nodes so the process is much faster as the action potential "jumps" from node to node.
55
describe the structure of skeletal muscles from largest to smallest?
whole muscle, fascicle, muscle cell/fibers, myofibrils, thick/thin filaments
56
what leads to muscle contraction?
thick and thin myofilaments sliding past one another
57
what proteins do thick myofilaments contain?
myosin
58
what proteins do thin myofilament contain?
actin, troponin, tropomyosin
59
what is a sarcomere?
a functional unit of the muscle cell. contractile unit. has actin and myosin
60
what cell has more than one nucleus? what are they covered with?
muscle cells. their nucleus is surrounded by sarcolemma.
61
describe the structure of thin myofilaments? include the proteins
mainly composed of actin which is twisted to form the backbone. has binding site for myosin. there protein strands of tropomyosin which cover the myosin binding site when the muscle is at rest. then there is troponin which as 3 subunits A,T,C. A binds to actin. T binds to tropomyosin. C binds to calcium. when calcium binds to troponin C, the troponin complex removes tropomyosin from the binding site
62
describe the structure of thick myofilaments? include the proteins. what does the splitting of ATP do here?
made up of myosin. has a long bendy tail and two heads that attach to the binding site on actin. the heads have ATP binding sites. the splitting of ATP releases energy to myosin powering muscle contraction
63
what is the sliding filament theory?
interaction between myosin and actin leads to muscle contraction. when myosin attaches to actin's binding site forming a crossbridge, myosin undergoes a change in shape and its head swings producing a power stoker which slides actin pass the myosin.
64
what shortens during muscle contraction? what doesnt?
scaromeres shorten during muscle contraction but thin and thick myofilaments do not
65
what is excitation-contraction coupling?
the action potential in cell membrane (sarcolemma) excites muscle cell leading to muscle contraction
66
what is the process of excitation-contraction coupling?
action potential generated at neuromuscular junction spreads over sarcolemma down the T-tubules to muscle cell's core. it goes close to sarcoplasmic reticulum and will open calcium channels releasing calcium from the terminal of it. the calcium binds to troponin C on the thin myofilaments. tropomyosin uncovers the myosin binding site on actin and now myosin can attach allowing power stroke. ADP and pi molecules released from myosin head.
67
rigor motis is when muscles become stiff after death. what is responsible for it?
due to the lack of ATP in dead muscles. the slow degradation of sarcoplasmic reticulum releases calcium. myosin binds to actin forming crossbridge between the myofilaments causing the muscles rigid conditions. without ATP the bond cant be broken until more cell degradation dissolves the linkage
68
what does ATP do in muscle contraction?
it splits into ADP and pi (inorganic phosphate). it releases energy to myosin. preps myosin head for activity. breaks the bridge between actin and myosin allowing contraction. pumps calcium back to end muscle contraction
69
how can the body alter forces of contraction?
thru recruitment of motor units or summation of twitch contractions
70
what is the recruitment of motor units?
continuous activation of motor units leading to more forceful contraction
71
what is a muscle twitch? what is the cause in delay of a muscle twitch?
simplest and smallest muscle contraction, it is the result of one AP in a motor neuron. a delay is due to the events at the neuromuscular junction
72
what is the summation of twitch contractions?
if muscle is stimulated again before it relaxes, the 2nd twitch would add to the 1st one meaning the tension in the muscle would be doubled. the twitch can be added but not the action potential
73
why cant muscles relax in the presence of action potential?
action potential causes calcium to be present which prevents muscles relaxing
74
what is the absolute refractory period?
sodium gates will not open so an action potential cant be launched. inactivation gate is closed and the channel is considered inactive
75
what is the relative refractory period?
when membrane is hyperpolarized. because potassium gates close slowly, an action potential can still be launched but a stronger stimulus is required
76
what are examples of negative feedback loops?
hormones, thermal regulation, blood pressure
77
what are examples of positive feedback loops?
action potential, breast milk production, labor contractions
78
what is it called when a cell goes to a more positive electrochemical state?
depolarization
79
where does action potential start?
at the axon hillock
80
where are the voltage gated channels?
at the axon hillock and at the nodes of ranvier or along axon
81
where is the threshold for action potential (charge)?
-55 mV
82
what are the steps of the neuromuscular junction?
action potential reaches axon terminal. calcium VGCs open allowing it to enter. this causes ACh synaptic vesicles to fuse with the plasma membrane. the ACh binds with the receptors. ligand-gated sodium and potassium channels open and sodium enters the muscle cell. this generates an end point potential, a depolarization which spreads and activates muscle fibers leading to contraction
83
from the side view, describe where the lobes are located.
in front is frontal lobe. in the back is the occipital lobe. on the bottom is the temporal lobe. on the top is the parietal lobe
84
what is the gyri and sulci?
gyri are bumps and sulci are dips in the brain which increase surface area
85
what is the frontal lobe responsible for?
movement
86
what is the parietal lobe responsible for?
sensory info
87
what is the temporal lobe responsible for?
auditory and smell (olfactory)
88
what is the occipital lobe responsible for?
vision
89
what are the types of neurons and where are they found?
bipolar cells have two process sticking out, found in retina. unipolar only have one process and found in peripheral nerves outside the CNS, theyre sensory and transmit to and from spinal cord. multipolar have many processes but only one axon and are found in CNS
90
what are glial cells?
they support cells of the brain. there is is usually 5 times more glial than neurons. they have a structural role and regulate nutrients and the environment of the brain
91
what are the parts of the frontal lobe and what do they do?
prefrontal cortex processes input and makes decisions. premotor cortex integrates info and determines steps for decision. primary motor cortex is movement
92
what are the parts of the parietal lobe and what do they do?
primary somatosensory receives sensory info from sensory organs. somatosensory associated area for cortex function
93
what are the parts of the temporal lobe and what do they do?
primary audio cortex and associated area for auditory processing. temporal lobe for olfaction, language, short term memory
94
what are the parts of the occipital lobe and what do they do?
primary visual cortex for visual input. visual associated area for visual integration
95
what are the types of postsynaptic potential? what can be said about both?
excitatory and inhibitory. they decrease over time and space and both can be summed to allow for it propagate
96
what is epsp?
excitatory postsynaptic potential that will open sodium channels and cause local depolarization
97
what is ipsp?
inhibitory postsynaptic potential that will open potassium channels and cause local hyperpolarization
98
what are the types of summation? what the difference between them
temporal and spatial. temporal summation is high frequency of action potential at one point on dendrite of postsynaptic neuron. spatial summation is low frequency at multiple points
99
what is synaptic integration?
a postsynaptic cell can receive many synapses which can produce ipsp, epsp, or even both. this depends on number of each postsynaptic potential present which will determine if cell depolarizes or hyperpolarizes
100
how is action potential generated at chemical synapse?
presynaptic neuron makes neurotransmitters. action potential in presynaptic neuron depolarizes membrane and opens calcium VGCs and it flows into axon terminal. this causes synaptic vesicles to attach to wall of synaptic terminal causing exocytosis and the release of neurotransmitters which diffuse across cleft to postsynaptic neuron and act on chemical receptors which cause chemically gated ion channels to open. lots of sodium flow in and some potassium flows out. depending on the neurotransmitter type, cell either depolarizes or hyperpolarizes
101
what are the types of muscle receptors and what do they detect?
muscle spindles detect muscle stretch, length, and rate of change of muscle length. golgi tendon detects muscle tension
102
describe muscle spindles
they are adjacent to extrafusal fibers and consists of intrafusal fibers, central sensory region, 2 sets of gamma motor neurons, and sensory neuron
103
what happens when muscle stretches? what is this an example of?
sensory region depolarizes and triggers action potential in sensory nerve and sends signal back to brain. the more stretched, the more depolarize, the more action potentials sent to the central nervous system. this is an example of proprioception
104
what does alpha-gamma coactivation do? why does it occur?
it ensures muscle spindles continue to send info about muscle and limb position during contract. it occurs because alpha motor neurons only causes extrafusal muscle fiber to contract so gamma motor neurons needed to contract intrafusal fibers which maintains stretch of center region. if only extrafusal contracts then info from muscle spindle will stop
105
what is an example of inhibitory neurotransmitter? excitatory neurotransmitter?
gamma amino butyric acid aka gaba is inhibitory while glutamite is excitatory
106
how does a reflex arc work? what is special about this.
starts in sensory receptor with receptor potential producing action potential in afferent neuron. action potential enters spinal cord producing action potential in interneurons and then efferent neurons which will activate the effector organ (muscle). special because it does not require output by the brain to cause the contraction
107
what does the cerebellum do? what info does it need?
helps generate accurate limb movement, correct ongoing movement, and modify strength of reflexes. it needs info from the motor cortex and proprioceptive from limbs. if muscle is not doing what its supposed to be doing it will modify info from primary motor cortex
108
what system influences normal behaviours such as heart rate, eating, sexual, memory, etc?
limbic system
109
what is the limbic system composed of?
hypothalamus, amygdala, hippocampus,
110
what is the autonomic nervous system? what are it's two subdivisions?
controls involuntary actions. divided into the parasympathetic nervous system and the sympathetic nervous system
111
what does the sympathetic nervous system do?
fight or flight. send neurons to each organ. excites. never exits spinal cord. preganglionic nerve synapse
112
what does the parasympathetic nervous system do?
preserver and stores. send neurons to each organ but not adrenal. inhibits. nerve exits at brain stem. postganglionic nerve synapse
113
what does the parasympathetic nervous system have no or very little effect on?
fat tissue, adrenal glands, kidney, blood vessels, etc
