phys final

define homeostasis

the state of dynamic constancy in the internal environment

what is negative feedback

a stimulus causes an opposite reaction by the body to bring the body back to its normal state

list in order the negative feedback mechanisms

1. stimulus - change that made you move away from set point

2. sensor - receptors receive and send info

3. control - CNS receives change and figures out how to correct it; asses change around a set point

4. effector - fix deviation from the set point

Look at the image and list the stimulus, sensor, integrating center, effector, and negative feedback response

stimulus: 1. BP falls

sensor: BP receptors respons

integrating center: medulla oblongata of brain

effector: heart - HR increases

negative feedback response: rise in BP

explain positive feedback

accelerates a process

• stimulus: causes deviation from set point

• cellular response amplifies deviation

• further deviation leads to additional cellular response

• and so on and so on until stimulus stops

• end product stimulates process

what are the three muscle types and which ones are voluntary and which ones arent

skeletal - voluntary

cardiac - involunatary

smooth - involuntary

what is the function of muscle and tissue cells

generate mechanical force

what do neurons do and what do they make up

conduct electrical signals/impulses to other cells (communicate); they make up the brain, spinal cord, and nerves

what are epithelaial cells and tissue specialized for (hint - list both single layer epithelium and multiple layer epithelium)

• single layer simple epithelium: secretion and absorption

• multiple layer stratified epithelium: protection

____ fluid is 65% of all fluid; ___ fluid includes plasma and interstitial fluid

intracellular; extracellular

list the 4 primary tissue types

• connective tissue, epithelial tissue, muscle tissue, and nervous tissue

What substance helps chemical reactions occur?

catalyst

what are the special molecules that catalyze biochemical reactions

enzymes

Describe facilitated diffusion

• no energy is required

• channel is specific and movements are diffusional

• an example is glucose - they are polar molecules that need a transported

• high to low movement through a membrane via protein channels.

describe active transport (general) - and then list the 2 types (you dont have to decribe the two types yet)

• involves energy (ATP) to pump a molecule up its gradient

• so low to high gradient

• molecule specific and limited by saturation and the rate of conformational change

• 2 types: primary and secondary

describe Primary active transport

• uses ATP pump; pump is an enzyme

• The Na/K pump

  • 3 Na⁺ ions out of the cell

  • 2 K⁺ ions into the cell
    per ATP molecule hydrolyzed.

describe the Na/K pump

• Binding of 3 Na⁺ ions from the cytoplasm (inside the cell) to the pump.

• ATP is hydrolyzed – one phosphate group is transferred to the pump (phosphorylation), providing energy.

• Pump changes shape and releases 3 Na⁺ ions to the outside of the cell.

• 2 K⁺ ions from outside bind to the pump.

• The phosphate group is released (dephosphorylation), causing the pump to return to its original shape.

• 2 K⁺ ions are released into the cytoplasm.

describe secondary active transport

• like primary active transport, it moves from low to high gradient

• differs because it does not directly use ATP

• relies on the energy stored in the gradient of another ion (usually sodium, Na⁺) that was established by primary active transport.

• requires that proteins have 2 binding sites (one for each molecule)

• 2 types: co-transport and counter transport

what are the 2 types of secondary active transport

co-transport and counter-transport

compare and contrast co-transport and counter-transport; make sure to list examples of each

• both secondary active transport

• Co:

  • symport

  • substances move in same direction

  • ex: K+,Cl- (renal system)

• counter:

  • antiport

  • substances move in opposite direction

  • ex: HCO_3-/Cl-

what kind of transport is A, B, and C?

A: Uniporter

B: Symporter; co-transport

C: antiporter: counter-transport

why do we have so much K+ in the cell?

• The Na/K pump actively brings in K+

• the membrane is very permeable to K+

• negative anions inside the cell attract the cations outside the cell

• this is where the body stores this molecule intracellularly

what are the values for restinf potential and threshold?

resting: -70 mV

threshold: -55 mV

what kind of neuron is located completely within the CNS and integrate the function of the nervous system

association/interneurons

what kind of neurons conduct impulses from the CNS to target organs (muscle or glands)

motor neurons

what kind of neuron conduct impulses from sensory receptors to the CNS

sensory neurons

___ speed up the conduction of electrical signals along an axon

myelin sheath

what forms the myelin sheath

oligodendrocytes

describe Ligand gated channel and where they are located

opening in response to binding of a chemical ligand to its receptors

location: on dendrites

describe voltage gated channels and where they are located

• opens in response to + or - changes

• protein channel when stimulated depolarizes the membrane to threshhold

• specific to an ion

• location: on axon

describe mechanical gates channels

• open when physical deformation to membrane occurs (like stretching)

define action potential

all or nothing event in a single cell where the membrane potential quickly becomes positive and returns to its resting potentials

what occurs during hyperpolarization

• Dips down past resting potential due to slow K+ moving out of the cell

depolarizaing ____ the permeability for Na+

increases

A second stimulus will not produce an action potential is called what

absolute refractory period

second action potential can happen only if stimulus strength is greater than usual is called what

relative refractory period

why do absolute refractory periods occur

• Na+ channels are
  inactivated

• As soon as inactivation is
  removed and Na+ are
  closed, the channel can
  reopen to second
  stimulus

____ of Na+ allpws action potential to travelw othout decrement (decrease)

positive feedback

synapses can use ____ and ____ stimuli to pass info

chemical and electrical

synapses can be ___ or ____ depending on the neurotransmitter being transmitted

excitatory or inhibitory

define synapse

a junction where impulses are transmitted from neurons and in the PNS the target muscle or gland

what connects electrical pre and post synaptic cells; and what is the speed of the flow

gap junctions; quick flow

where are electrical synapses found; why?

cardiac and smooth msucle; allows for contractions as a unit to occur

describe an excitatory post synaptic response

• Opening Na+ or Ca2+ channels results in a graded depolarization called an excitatory postsynaptic potential; activated 

• on the ligand gated channels on the dendrites 

• The dendrite is the area for graded potential 

• Na or Ca go into the cell

describe an inhibitory post synaptic response

• Opening K+ or Cl- channels results in a graded hyper-polarization called inhibitory postsynaptic potential

• Hyper-polarization

• K+ moves out and Cl- moves in 

what are the characteristics of graded potentials

summation and lack of refractory period

AcH channels are ___ gated channels

ligand

step by step explain how an action potential is produced

1. Resting Potential (~ –70 mV)

• The neuron is at rest.

• The Na⁺/K⁺ pump maintains high Na⁺ outside and high K⁺ inside.

• Inside of the cell is negatively charged compared to the outside.

• Voltage-gated channels are closed.

2. Stimulus and Threshold (-55 mV)

• A stimulus (e.g., neurotransmitter binding) causes local depolarization.

• If the membrane potential reaches threshold (~ –55 mV), an action potential is triggered.

• Voltage-gated Na⁺ channels open.

3. Depolarization (rises to +30 to +40 mV)

• Na⁺ floods into the cell due to concentration and electrical gradients.

• The membrane potential becomes more positive.

• Rapid upward spike in voltage.

4. Peak of Action Potential (+30 to +40 mV)

• Voltage-gated Na⁺ channels close (inactivate).

• Voltage-gated K⁺ channels open.

5. Repolarization

• K⁺ exits the cell, making the inside more negative again.

• Membrane potential starts to return toward resting level.

6. Hyperpolarization (~ –80 mV)

• K⁺ channels stay open slightly too long, causing the membrane to become more negative than the resting potential.

• Prevents immediate firing again (refractory period).

7. Return to Resting Potential

• Voltage-gated K⁺ channels close.

• Na⁺/K⁺ pump and leak channels restore original ion concentrations.

• Neuron is back to –70 mV, ready to fire again.

Explain how ligand-gated channels produce synaptic potentials, using the nicotinic ACh receptor as an example. 

1. An action potential reaches the presynaptic neuron terminal.

2. This triggers release of acetylcholine (ACh) into the synaptic cleft.

3. ACh Binds to Nicotinic Receptors

4. ACh diffuses across the cleft and binds to nicotinic ACh receptors on the postsynaptic membrane.

   • These receptors are ligand-gated ion channels.

5. Binding of ACh opens the channel, allowing Na⁺ to enter and K⁺ to exit the postsynaptic cell.

6. However, more Na⁺ enters than K⁺ leaves, leading to a net positive charge inside.

7. This net inward flow of positive charge depolarizes the postsynaptic membrane.

8. If the EPSP is strong enough to reach threshold, it can trigger an action potential in the postsynaptic neuron.

9. To end the signal, acetylcholinesterase breaks down ACh in the synaptic cleft.

10. The receptor channels close, and the membrane potential returns to baseline.

what are the receptors that Ach can bind to

nicotinic and muscarinic

MODULE 7

MODULE 7

what are the functions of the CNS

.1. Receives input from sensory neurons and
directs activity of motor neurons
2. Association neurons integrate sensory
information and help direct the appropriate
response to maintain homeostasis and respond
to the environment

what portion of the brain controls emotion

limbic system

what all does the hippocampus do

Formation and retrieval of memory
• Helps form cognitive maps that help make mental models
of our world
• Stress and emotion (via thelimbic system) can affect
memory
• Contain Cortisol receptors

what is the master command center for neural and endocrine coordination

hypothalamus

what regulates the pituitary gland

hypothalamus

what two hormones does the hypothalamus produce

antiduretic (ADH) and oxytocin

what is the limbic system made up of

thalamus and hypothalamus

what does the thalamus do

•  relay center for sensory info (except smell); direction of traffic; helps the flow of info, allowing you to prioritize what is received 

what do opioid neurotransmitter bind to

opioid receptors

what are opioid receptors activated by

stress to block the transmission of pain

what is the part of the hindbrain that has the ability to control rates; ex: heart rate

medulla oblongata

what neurotransmiter is involved in memory, sensory, and learning

glutamate

what is dopamine involved in

mood, sleep, reward pathway, effected by increase in pressure

what are beta endorphine involved in

• released when the body feels pain

• runners high

• will decrease anxiety

what is GABA involved in

• its your inhibitory neurotransmitter

• involved in brain function and sleep

• Lets help someone sleep by reducing senses

in the reflex arc, A ___ occurs at the receptor of a ____. This is sent along the _____ as a nervous impulse and is received by the ___

stimulus; sensory neuron; afferent neuron; CNS

in the reflex arc, the interneuron makes connections to the ____. the ____- transmits the impulse to the ____

motor neuron; motor neuron; effector organ

MODULE 8

MODULE 8

what are the subdivisions of the autonomic division

parasympathetic, sympathetic, and enteric

Which neurotransmitter is only in the sympathetic division

norepinephrine

what are the types of adrenergic receptors and what do they use

a(alpha) - a1 and a2; use cAMP

B (beta) - B1 and B2; use a Ca2+ second messenger system

___ receptors are more sensitive to norepinephrine

Alpha (α) receptors

____ receptors are more sensitive to blood epinephrine

beta (β) receptors

what is dual innervation

One organ receiving sympathetic and parasympathetic input, usually with opposing effects that help maintain balance (homeostasis).

Apply examples of dual innervation of the sympathetic and parasympathetic divisions of the autonomic system

Ex 1: Heart

• Sympathetic: Increases heart rate and force of contraction
  (via norepinephrine on β1 receptors)

• Parasympathetic: Decreases heart rate
  (via acetylcholine on muscarinic receptors)

Ex 2: Urinary Bladder

• Sympathetic: Relaxes bladder wall, contracts internal sphincter
  (inhibits urination)

• Parasympathetic: Contracts bladder wall, relaxes sphincter
  (promotes urination)

what hormone does the medulla oblongata secrete

epinephrine

what do the postganglionic neurons release

norepinephrine

___ is released; ___ is secreted

norepinephrine; epinephrine

during fight or flight, HR ____ and BP _____

increases; increases

the parasympathetic division is ____ to the sympathetic division

antagonist

what does the parasympathetic division do/rest and digest

• Releases ACh from postganglionic neurons

• Slows heart rate (decreases rate of pacemaker cells), and
  increases digestive activities

the automatic system is moves ___ from the spinal cord, making it ___

away; efferent

what are the neuotransmitters and receptors for the parasympathetic division - acknlowledge pre and post ganglionic

Preganglionic neurotransmitter: Ach

Preganglionic receptor: nicotinic

Postganglionic neurotransmitter: Ach

postganglionic receptor: muscarinic

what are the neuotransmitters and receptors for the sympathetic division - acknlowledge pre and post ganglionic

Preganglionic neurotransmitter: Ach

Preganglionic receptor: nicotinic

Postganglionic neurotransmitter: norepinephrine

Postganglionic receptor: adrenergic (alpha and beta)

MODULE 9

MODULE 9

The function of the endocrine system is to ____

regulate

define hormone

a chemical message produced by an endocrine tissue and travels through the bloodstream to target cell receptor

what hormones are released by the posterior pituitary and what do they do

• oxytocin - involved in milk ejection reflex

• ADH (vasopressin) - involved in regulation of water

the ___ pituitary is controlld via releasing and inhibiting hormones transported through the ______

anterior; hypothalamo-hypophyseal portal system

what is the sequence of events of the hypothalamo-hypophyseal portal system?

1. regulatory hormone controls secretion of anterior pituitary

2. anterior pituitary hormone then controls the secretion of a hormone from another endocrine gland

3. the last hormone does the action on its target cell

   ex: thyroid releases T3 and T4 hormones to do the action intended of this sequence

what are the pancreatic hormones and what do they regulate

glucagon and insulin; Regulates blood glucose levels, causes an antagonistic effect (blocking)

insulin ___ blood glucose levels; glucose ____ blood glucose levels

lowers; raises

The hypothalamo-hypophyseal tract is a neural pathway that connects the ___ to the _____ (neurohypophysis)

hypothalmus to the posterior pituitary gland

MODULE 10

MODULE 10

What are thick filaments made up of; thin filaments?

myosin; actin

____ is on actin and blocks the cross bridge

tropomyosin