topic 9. powerpoint 9.1

Question 1

What is cardiac output

Answer 1

CO= SV x HR

Question 2

What is the difference between preload and afterload?

Answer 2

preload is end-diastolic volume aka amount of ventricular stretch
Afterload: the amount of pressure needed in the ventricles to surmount the aortic
and pulmonary pressure and thus propel blood into the aorta and lungs

Question 3

How can the force of contraction be varied to change the stroke volume?

Answer 3

More blood returns, increases preload because end-diastolic volume is greater. This increases contractions and thus stroke volume(ml/beat pumped out left ventricle)

Question 4

What is a sarcomere?

Answer 4

Functional unit of contraction of muscle fiber. Made up of myofilaments, actin and myosin. During muscle contraction, myosin heads attaches to actin and pulls towards center of sarcomere, causing muscle to shorten. Slide mechanism allows for movement

Question 5

Frank-Starling Mechanism

Answer 5

physiological mechanism that allows the heart to adjust its pumping strength[increase contraction] based on the volume of blood it receives[preload]

Question 6

If the ventricular end diastolic volume increases, we can expect the ___ to increase

Answer 6

stroke volume
EDV happens before SV

Question 7

Besides greater blood return influencing contraction, what 2 other things can affect the force of contraction?

Answer 7

-Sympathetic Activity
-Parasympathetic Activity

Question 8

Sympathetic Activity and Parasympathetic Activity can innervate the heart by?

Answer 8

influencing heart rate and stroke volume, ensuring that bp, blood O2/ CO2, and blood PH are in homeostasis

Question 9

What are the two parts of the nervous system?

Answer 9

CNS: central nervous system
-brain and spinal cord
PNS: peripheral nervous system
-connect CNS to limbs and organs
-afferent and efferent

Question 10

PNS has what two divisions?

Answer 10

Afferent: transmit signals to CNS
*includes sensory neurons/transmits sensory info
Efferent: transmit signals from CNS
**carries signals to muscles and glands

Question 11

Efferent system has what two divisions?

Answer 11

Somatic:
Autonomic

Question 12

What is somatic?

Answer 12

One of the two efferent divisions:
-mostly voluntary
-controls movements that are conscious
-utilizes motor neurons
-carries efferent signals from CNS to skeletal muscle

Question 13

What is ANS?

Answer 13

The autonomic nervous system, one of the two efferent divisions
-a collection of motor neurons(ganglia) and the axonal connections of those neurons
-functions below the level of consciousness(involuntary)

Question 14

Name the two divisions of the ANS?

Answer 14

Sympathetic
Parasympathetic

Question 15

Sympathetic division

Answer 15

Fight or flight
Response to high emotional activity can result in increased bp, heart rate, suppress digestion

Question 16

Parasympathetic division

Answer 16

Rest and digest
-located around the sympathetic nerve
-house keeping functions like digestion

Question 17

What is the vagus nerve?

Answer 17

Cranial nerve 10, conveys sensory info about the state of the viscera to the CNS
viscera-internal organs such as those in abdominal regions

Question 18

Vagus nerve carries ___ to the
heart (primarily)

Answer 18

parasympathetic nerve fibers

Question 19

Parasympathetic nerve stimulation has an ____ effect-decreases____

Answer 19

inhibitory, heart rate

Question 20

Explain how parasympathetic nerve stimulation decreases heart rate

Answer 20

Parasympathetic neurons are found in the vagus nerve, produce acetylcholine and exerts an inhibitory effect on ligand gated channels on cardiac cell membrane channels in the SA node by forcing k+ out, causing hyperpolarization. Hyperpolarization takes longer to depolarize, resulting in decrease in heart rate.

Question 21

Neurotransmitter receptors can be classified into two categories:

Answer 21

metabotropic and ionotropic,

Question 22

What is the difference between metabotropic and ionotropic?

Answer 22

Ionotropic receptors form an ion channel pore, while metabotropic receptors are indirectly linked with ion-channels through signal transduction mechanisms.

Question 23

Acetylcholine binds to what receptor in the heart?

Answer 23

Metabotropic receptors; Muscarinic acetylcholine receptors

Question 24

After acetylcholine binds to M2 Muscarinic receptors in the heart causing a inhibitory effect, the ___ can have stimulatory actions on the heart.

Answer 24

sympathetic nervous system

Question 25

How does the sympathetic nervous system increase heart rate?

Answer 25

Sympathetic nerves from the thoracic region of the spinal cord project to the heart as cardiac nerve and innervate various components, increasing heart rate and force of contraction.

Question 26

what is the cardioregulatory center?

Answer 26

A region in the brainstem(medulla) that is responsible for regulating and controlling the activity of the heart by sending signals to the heart via the autonomic nervous system to adjust heart rate and force of contraction.

Question 27

parasympathetic nerve fibers extend to heart via __ and sympathetic nerve fibers extend to heart via ______

Answer 27

vagus nerve, cardiac nerve

Question 28

How is epinephrine/norepinephrine secreted? Effect?

Answer 28

Sympathetic nerve fibers extend to adrenal medulla, sympathetic neurons increase secretion of epinephrine and norepinephrine, which increase HR and SV

Question 29

How does norepinephrine have a stimulatory effect?

Answer 29

Increases the rate and degree of cardiac muscle depolarization, which causes an increase in the frequency of the action potential and the force and velocity of the
contraction.

Question 30

Sympathetic effect results in increase in HR and SV, what two neurotransmitters are involved?

Answer 30

norepinephrine & epinephrine; which are classified as catecholamines aks derived from tyrosine *also act as hormones

Question 31

Norepinephrine and epinephrine, which is derived from the other?

Answer 31

Epinephrine is derived/synthesized from norepinephrine

Question 32

norepinephrine and epinephrine bind to what receptors?

Answer 32

note: both are catecholamines
Catecholamines bind to two different classes of receptors termed the α- and β-
adrenergic receptors

Question 33

activation of β-adrenergic receptors leads to what?

Answer 33

can lead to an increase in heart rate and force of contraction.

Question 34

how can you remember what neurotransmitter binds to α- and β-
adrenergic receptors?

Answer 34

adrenergic = adrenaline aka epinephrine
answer: epinephrine and norepinephrine

Question 35

Epinephrine and norepinephrine are also called___

Answer 35

adrenergic neurotransmitters;

Question 36

Noradrenergic neurons specifically secrete ___ as a neurotransmitter, while ___ secrete both norepinephrine and epinephrine.

Answer 36

norepinephrine, adrenergic neurons

Question 37

agonist

Answer 37

agonist is a substance or molecule that activates or stimulates a receptor in the body

Question 38

norepinephrine is what class of neurotransmitter?

Answer 38

Norepinephrine is metabotropic.

Question 39

norepinephrine acts as an agonist for what? Explain the process

Answer 39

β-adrenergic receptors
1. metabotropic neurotransmitter, causes G-protein mediated synthesis and accumulation of cAMP
2. Ca+ channels open on plasma membrane and sarcoplasmic reticulum allowing depolarization
3. calcium troponin reaction
4.reuptake of Ca+ into SR
-overall it’s how increased force and velocity of contraction, HR is up

Question 40

explain the calcium troponin reaction

Answer 40

Within cardiac muscle cells, calcium ions bind to troponin, it causes a conformational change that allows the actin and myosin filaments in the muscle fibers to interact and slide past each other, resulting in muscle contraction

Question 41

Besides increasing force and velocity of contraction, what other sympathetic activities is epinephrine involved in?

Answer 41

increases cardiac output and blood glucose levels

Question 42

if Ca+ enters back into the sarcoplasmic recitulm, what can we expect?

Answer 42

heart to relax, when Ca+ was leaving it increased heart rate and so we can expect the opposite

Question 43

How can we increases heart rate?

Answer 43

beats can be shorter
resulting in more beats per unit time

Question 44

By increasing contractility, you…

Answer 44

more completely empty the heart of blood because increased contraction means more blood is pumped out

Question 45

t/F if you have the same end diastolic volume, you can’t increase heart contracility

Answer 45

false, the heart muscle is able to generate a stronger force of contraction, resulting in more blood being pumped out of the ventricles per beat. Ex: epinephrine can make this happen