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PE 220 Unit 1

Terms in this set (116)

Physiology
The study of body function
Homeostasis
process by which organisms maintain a relatively stable internal environment

-requires a balance of PNS and SNS
exam is worth
20%
set point (homeostasis)
target amount for a certain variable
variable in homeostasis
the factor or event being regulated
something that can change by
Receptor (homeostasis)
responds to changes in the environment and sends information to the control center
Effector (homeostasis)
carries out instructions
receives information from the control center and responds

ex- o2, blood pressure, co2, energy stores, core temperature
control center (homeostasis)
processes the signal and sends instructions
law of mass balance
if the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss

input greater than output= net increase
input less than output= net decrease
Equilibrium
A state of balance
system stable physical variable constant
steady state
a state in which inputs equal outputs so that the system is not changing over time
steps in a response pathway
stimulus (receptor) -> integration of signal (control center) -> response (effector)

positive and negative feedback loops
positive feedback
effector same direction as the stimulus and continues to amplify the change, moves further away from the stimulus
positive feedback example
childbirth and blood clotting

blood clotting: platelets adhere to injury, chemicals release, more platelets are attracted, more chemicals are released, and continues until there is a clot
negative feedback
effector opposes the stimulus, shuts off when conditioning goes back to normal, is more common
negative feedback example
body temperature

goes to hypothalamus, brain send signals to sweat glands, body temp goes normal and sweating ends
feedforward response
conscious response when prepared (proactive)
Core Concepts
fundamental ideas that are helpful in analyzing features
cell membrane
A cell structure that controls which substances can enter or leave the cell.
cell to cell communication
a form of cell communication that occurs between two different cells

cells talking to each other
flow down gradients
the transport of stuff is a central process at all levels of organization in the organism, and this transport is described by a simple model.
interdependence
all physiological systems rely on each other
mass balance
the quantity of stuff in any system or in a compartment in a system is determined by how much you are bringing in and how much you are losing

net change= input-output
gradient example
gradient concentration- more K+ inside a cell, than outside
interdependence example
nutrients get from digestive system to muscular system from the cardiovascular system
mass balance example
average male 70 kg (150-160 lbs), of those 70 kg, more than half (40 L) are body fluids. 7L that are secreted daily make about 20% of the total fluid in the body on a daily basis.
explain the role of atp in the cell
1 molecule of adenosine and 3 phosphate groups
-formed from adp
-energy that is released from atp is broken back down into adp
-ATP is broken down and energy creates movement and is released as heat
simple diffusion (passive transport)
Passive movement from high to low concentration directly through the membrane

-energy comes from concentration gradient
-ions move DIRECTLY through membrane
facilitated diffusion (passive transport)
Movement of particles from high concentration to low concentration through a protein carrier.

-energy comes from concentration gradient
-ion movement REQUIRES interaction with the protein a crossed the membrane
active transport
Energy-requiring process that moves material across a cell membrane against a concentration difference

-goes against the gradient
-energy comes from ATP
-ion movement REQUIRES interaction with protein AND energy
Osmosis
Diffusion of water through a selectively permeable membrane; concentration of a solute in a solution

-energy comes from concentration gradient
-can dissolve in a solution
Define resting membrane potential (RMP)
the amount of stored energy (potential energy) across the membrane when an excitable cell is at rest

na closes fast and k closes slow

-70 MV is the charge
-steady state
-Na influx (inside) (less negative)
-K efflux (outside) (more negative)
-Na/K pump (more negative)
-proteins (more negative)

na inactiv- open
na activ-closed
k-closed
ion concentration gradient
the difference in amounts of ions in separated places can create a flow
membrane permeability
degree to which a membrane allows a substance to pass through it

higher permeability more doors open
Explain how sodium-potassium ATPase pumps help maintain the resting membrane potential.
3 Na out (na closes fast)
2 K in (k closes slow)
requires atp and active transport

negative inside and positive on outside of the cell
inside: negative proteins, and K leak channels
outside: Na leak channels

potassium is brought INSIDE through leak channels and sodium goes OUTSIDE, this helps maintain the ion concentration gradient and produce negative membrane potential neurons

no leak channels in a pump
Define the term cellular respiration
reaction of oxygen with molecules to produce energy, co2, and h20
-aneraobic (no o2)= glycolysis
-aerobic= krebs and ETC
Glycolysis
the breakdown of glucose by enzymes, releasing energy and pyruvic acid.
-no oxygen
-cytosol
-glucose is converted into pyruvate and if oxygen is not present then glucose is converted into lactate
-NADH and atp (4) are the products
Krebs cycle
second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

-oxygen
-matrix of mitochondria
-pyruvate is converted into acetyl-CoA
-produces co2, 2 atp, and nadh2
electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

-oxygen
-inner membrane of mitochondria
-nadh and fadh2 give off hydrogen ions as they travel through a large hydrogen gradient combined to ADP and P, hydrogen then leaves and binds with oxygen to produce water
-produces 32 atp, water
describe the major functions of the nervous system
sensory= receives information about the environment
integration= processes information
respond= responds to receive information
peripheral nervous system
the sensory and motor neurons that connect the central nervous system to the rest of the body

-autonomic and somatic
-contains afference and efferent pathways
-relays information between the central nervous system and the body
central nervous system
consists of the brain and spinal cord
-contains efferent pathways
-integration center
efferent neurons (motor neurons)
neurons that take information from the brain to the rest of the body
afferent neurons (sensory neurons)
neurons that take information from the senses to the brain
describe the nervous system as a control system with the following components: sensory receptors, afferent pathways, control (integrating) center, efferent pathways, and effector (target) organs.
stimulus happens, travels to sensory receptor, to the afferent neuron to the integration center (CNS), then goes back down to the efferent neuron to that specific organ (efferent organ) and then responds

the control system manages, commands, directs, or regulates behavior of other devices of systems
somatic motor neurons
responsible for reflexes and voluntary control of skeletal muscles
autonomic motor neurons
innervate involuntary targets such as smooth muscle, cardiac muscle, and glands
somatic sensory
carries signals from receptors in the skin or muscles (five sense)
visceral sensory
receives sensory information from viscera (internal organs)
major ion channels of neurons
active ion channels and passive ion channels
active ion channels
requires a stimulus to open, they have a door
-voltage gated or ligand
passive ion channels
are always open and allow specific ions to move down their concentration gradients
-helps to establish membrane potential
-leak channels
voltage gated channels
open and close in response to changes in membrane potential, change in voltage/charge

along the axon, synapse
ligand-gated ion channel
chemical binds and opens channel

along the dendrites, synapse
concentration gradient
difference in the concentration of a substance from one location to another
-movement of ions from increase to decrease

sodium is more likely to move to the inside the cell
Relative Ion Concentrations
more potassium inside membrane and more sodium outside
electrochemical gradient
based on the concentration and electrical gradient

electrical gradient-movement of ions towards their opposite charge (positive attracted to negative)
Describe the role of the sodium-potassium ATPase pump in maintaining the resting membrane potential
maintains two ion concentration gradients and produces the negative membrane potential in neurons
action potential
the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.
Depolarization
-55 mv to 30 mv

sodium activ and inactiv open which causes a sodium influx, potassium gates open but slowly

less negative
Repolarization
30mv to -70mv

sodium inactiv close at 30 mv, sodium activ is closed, and potassium is slowly opening all the way

potassium efflux
Hyperpolarization
first phase:
-drops below threshold and gates reset (sodium inactiv open, sodium activ and potassium closed)
-potassium efflux occurs until gates are completely closed
-membrane potential drops to -85mv

second phase:
-returns back to -70mv
-potassium influx occurs
-proteins pull the potassium ions back into the cell

sodium inact-open
sodium activ-closed
potassium-closed slowly
Threshold
the level of stimulation required to trigger a neural impulse
graded potential vs action potential
graded:
not as strong as action potential, it doesn't break threshold, shorter and weaker

a shift in electrical charge in a tiny area of the neuron (temporary)
-beginning of the axon to initiate an action potential; postsynaptic cell
-they can be depolarizing or hyperpolarizing
-ion channel: ligand-gated
-ions: Na, K, Cl
-temporal summation and spatial summation
-no refractory period

action:
-depolarize
-ion channel: voltage-gated channels
-ions: sodium and potassium
-absolute and relative refractory periods
-occur in the plasma membrane
importance of voltage-gated channels in an action potential.
key signal of electrical excitability, converting the electrical signal of the action potential in the cell surface

Two types of voltage-gated channels: potassium channels and sodium channels.

Each potassium channel has, a single gate that is voltage-sensitive; it is closed when resting and opens slowly in response to depolarization
explain how axon diameter and temp affect conduction velocity.
large diameter=more lanes, less congestion for ions which allows them to travel faster

higher temp=faster conduction increased temperature increases the speed of ions
explain the role of myelin in saltatory conduction.
myelin prevents ions from entering or exiting the nerve cell

saltatory is like a leap:
na rushes into the cell, na already in the cell is pushed forward, causes voltage gated channels to open at the next node, node needed because na can only be "pushed" so far; relatively quick
action potential conduction in an unmyelinated axon
the conduction rate is relatively slow
action potential conduction in a myelinated axon
myelin greatly speeds up action potential conduction
absolute refractory period
absolutely nothing can be received

The minimum length of time after an action potential during which another action potential cannot begin.

depolarization= Na activ gates are open; can't open a door that is already open

repolarization= na inactiv gates are closed
relative refractory period
stimulus can be received but it has to be larger than normal

A period after firing when a neuron is returning to its normal polarized state and will fire again only if the incoming message is much stronger than usual

hyperpolarization
Synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
electrical synapse
Direct connection between two cells so that ions can pass directly from one cell to the next
chemical synapse
neurotransmitter acts as signal from presynaptic to postsynaptic cell
ionotropic receptors
fast-open an ion channel when the transmitter molecule binds

fast synaptic responses
metabotropic receptors
Slow-acting receptor type composed of a single large protein in the cell membrane that activates G proteins. It may also be called a G protein-coupled receptor.

slow synaptic responses
G proteins explain
hormone binds to receptor
GDP leaves, GTP enters
GTP and alpha leave and bind to a protein

-the receptors open the ion channel and/or activation of second messenger (enzymes)
excitatory postsynaptic potential (EPSP)
a slight depolarization of a postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for an action potential
inhibitory postsynaptic potential (IPSP)
an inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button
temporal summation
single neuron sends same signal, repeatedly over time, high frequency
spatial summation
multiple neurons send signals at the same time
summation
results in depolarization or hyperpolarization of graded potentials

-sum of the graded potential
Describe the different mechanisms (e.g., reuptake, enzymatic breakdown, diffusion) by which neurotransmitter activity at a synapse can be terminated
Neurotransmitters are removed from the synaptic cleft by diffusion out of the cleft, removal by an enzyme, or via re-uptake pumps that actively pump the neurotransmitter back into the presynaptic axon.
Define the term reflex
response to stimulus
reflex arc
the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between.

1. receptor
2. sensory neuron
3. integration center
4. motor neuron
5. effector
intrinsic reflex
a rapid, involuntary, predictable motor response to a stimulus
learned reflex
reflex acquired through experience
somatic reflexes
activate skeletal muscle
visceral reflexes
unconscious, automatic, stereotyped responses to stimulation involving visceral receptors and effectors
monosynaptic reflex
Reflex pathway with only one synapse between the sensory and motor neurons (ex: knee-jerk).
polysynaptic reflex
at least one interneuron between sensory neuron and motor neuron
contralateral reflex
sensory input from opposite side as motor output
ipsilateral reflex
stimulus and response are on the same side of the body
stretch reflex
the contraction of a muscle in response to stretch of that muscle
tendon reflex
reflexive contraction of a muscle when its tendon is tapped
flexor reflex (withdrawal reflex)
initiated by painful stimulus like touching something hot and causes quick withdrawal/flexion of limb
crossed extensor reflex
opposite limb supports body during withdrawal of injured limb
somatic nervous system
-consists of one motor neuron
-starts in ventral horns of spinal cord
-myelinated
-releases acetylcholine
autonomic nervous system
-2 neurons
-start in lateral horns in spinal cord
-myelinated and unmyelinated
-releases acetylcholine and norepinephrine
-efferent pathway
sympathetic nervous system
fight or flight
-increases heart rate and blood pressure
-shifts blood flow to skeletal and cardiac muscle
-can occur in response to something or in anticipation of something
parasympathetic nervous system
rest and digest
-stimulates digestion
-blood flow can be directed to your digestive system
dual innervation
most viscera receive nerve fibers from both parasympathetic and sympathetic divisions
origin of sympathetic nervous system
thoracic and lumbar regions of spinal cord (middle and lower back)
origin of parasympathetic nervous system
brain stem and sacral region of the spine
sympathetic anatomy
preganglionic:
short, myelinated
releases acetylcholine and binds to nicotinic cholinergic receptor

post ganglionic:
long, unmyelinated
releases norepinephrine and binds to adrenergic receptor


exception with adrenal gland:

preganglionic:
short, myelinated
innervates with adrenal gland and releases epinephrine
parasympathetic anatomy
preganglionic:
long, myelinated
acetylcholine is released and binds to nicotinic cholinergic receptor

postganglionic:
short, unmyelinated
releases acetylcholine and binds to cholinergic or muscarinic cholinergic receptors
fastest acting is what
parasympathetic because of myelin
longest acting is what
sympathetic
Describe visceral reflex arcs, including structural and functional details of sensory and motor (autonomic) components
(Visceral reflexes: unconscious, automatic, stereotyped responses to stimulation ANS in charge of these reflexes)
1. Receptor: nerve endings that detect stimuli
2. Afferent (sensory) neurons: lead to the CNS
3. Interneurons
4. Efferent (motor) neurons: carry motor signals away from CNS
5. Effectors: respond to motor signals
cholinergic receptors (g protein receptors)
-nicotinic and muscarinic
-location: the surface of muscle cells
-target cell response: excitatory
-neurotransmitters that bind to them: norepinephrine
adrenergic receptors (g protein receptors)
-location: secretory terminals of some postsynaptic adrenergic neuron
-target cell response: may have an excitatory or inhibitory effect
-receptor sites for the sympathetic neurotransmitter's norepinephrine and epinephrine
what causes exocytosis
Calcium influx

exocytosis is a process by which a cell releases large amounts of material
what neurotransmitter active ion channels
adrenergic and muscarinic receptor (go to the heart)
what tells the CNS the length of muscle?
muscle spindle
what activates-agonists or antagonists
agonists
a and b are talking to c it is
spatial summation
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