9.1 Cardiac Output

To vary stroke volume, the force of ______________ must be varied

contraction

The amount of blood pumped out is proportional to the how much blood is _____________ to the heart

returned

The frank-starling mechanism is that

an increase in stretch leads to increase in force

In the heart at rest the muscle is ____ at optimal length

not

__________________ and _______________ nerve fibers innervate the heart

Parasympathetic and sympathetic

The parasympathetic and sympathetic system affects both heart _________ and stroke ___________

rate; volume

The _______ nerve carries parasympathetic nerve fibers to the heart

Vagus

The Vagus nerve innervates the ____ node which is the hearts ___________

SA; pacemaker

The parasympathetic nerve stimulation has a ____________ effect which means it _______________ heart rate

inhibitory; decreases

Parasympathetic neurons produce the neurotransmitter ___________________

Acetylcholine

In the parasympathetic system, acetylcholine binds to ligand gated channels on cardiac cell PM which caused K+ to go _______. this also decreases the permeability of _____________ and ____________

out; sodium and calcium

When acetylcholine acts on the heart, the membrane is ________________ so it is harder to create and AP and heart rate _________

hyperpolarized; decreases

The acetylcholine metabotropic receptor is called ____ ________________ receptor

M2 muscarinic

The sympathetic nerves from the _____________ region of spinal cord project to the heart as __________ nerves

thoracic; cardiac

Sympathetic nerves innervate the ____ and ____ nodes, the coronary vessels and the ___________

SA and AV; myocardium

Sympathetic stimulation ___________ heart rate and force of muscular contraction

increases

insert nervous system regulation photo

The main neurotransmitters related to the sympathetic system and the heart are ________________ and ____________

norepinephrine and epinephrine

Norepinephrine and epinephrine (adrenaline) are classified as ______________ which are amines derived from the amino acid __________

catecholamines; tyrosine

___________ is synthesized from norepinephrine

epinephrine

Catecholamines are also known as ____________ neurotransmitters that bind to ______ and ______ adrenergic receptors

adrenergic; alpha and beta

Norepinephrine-secreting neurons are _____________

noradrenergic

Norepinephrine is from ________________ sympathetic neurons

postganglionic

Norepinephrine increases the _____ and ______ of cardiac muscle ____________ which causes an increase in frequency of AP

rate and degree; depolarization

When norepinephrine binds to ___ adrenergic receptors, a G-protein mediated synthesis of ________. This opens _____ slow receptors which increases the cells ability to depolarize. This also helps to open ____ channels

Beta; cAMP; Ca2+; Na

insert mechanisms of sympathetic effects

Epinephrine is released from the _________ __________

adrenal medulla

In sympathetic activity nerve signals to the adrenal gland to convert _____________ to _______________ which increases cardiac output and blood _________ levels

norepinephrine to epinephrine; glucose

Adrenaline is released during increases physical activity, emotional __________ or ___________ situations and causes sympathetic stimulation of cardioregulatory center in brainstem the __________

excitement; stressful; medulla

Epi and norepi bind to ___ ___________ receptors

B adrenergic

Norepi and epi prepare the body for fight or flight by increasing ______________ and _____________ and upregulating the _______ and ______ supply to muscle tissue

blood pressure; heart rate; blood and oxygen

During sympathetic activation, heartbeat is stronger and shorter due to increased rate of _____________ release/entry and increased rate of _________ uptake

calcium; calcium

Adrenaline affects the channels that bring calcium _________ the cell, the channels that allow Ca 2+ to leave and reenter the ___________ ___________ and the calcium and ___________ interaction

into; sarcoplasmic reticulum; troponin

The sympathetic system has an effect on contractility, meaning for the same volume, the heart contracts _________

stronger

The sympathetic system allows the heart to be completely ___________

emptied

insert summary effects of autonomic nerves