control heart rate - animal response

which division of the nervous system involved in conscious activity ?

Somatic nervous system

which division of the nervous system involved in slowing down activity?

Parasympathetic Nervous system

which division of the nervous system controls the heart rate ?

Parasympathetic and sympathetic nervous system

as it’s self governing.

what does the parasympathetic nervous system do ? 

it inhibits effectors 

what does the sympathetic nervous system do ? 

it simulates effectors 

what are the parasympathetic and sympathetic nervous system known as ?

Two system : antagonistic

Facts - cardiac muscle

self governing

its branched

cells contract in 3 dimensions. 

what are the pacemaker cells called in the heart ?

SAN sino atrial nodes

what does the SAN sino atrial nodes does

controls frequency of heartbeat.

Initiate stimulus for contract.

generates action potential 

what’s another word for impulses ?

action potential

describe how an impulse ( action potential ) spread throughout the heart ?

SAN generates an action potential, and depolarisation spreads over the atrial muscle ( cardiac muscle).

AV septum is non conductive, to prevent AP from traveling down over the ventricles wall. 

The AP pauses at the AVN, allowing time for atria to fully contract + empty out the blood into the ventricles before the ventricles contracts. 

AP travel down ‘ bundle of his through punrkinje tissue over ventricle  muscle. 

how it the change of heart rate controlled ?

Controlled in the brain by medulla which contains ‘ cardio regulatory centre. 

what are the 2 divisions of cardio regulatory centre ? 

cardio acceleratory centre and cardio deceleratory 

what does the cardio acceleratory centre do ? 

uses sympathetic nerve fibers ( via acceletpr nerve) to increase heart rate and contractility, which is part of the "fight or flight" response.

More frequent action potential to SAN 

what does the cardio deceleratory  centre do ? 

uses parasympathetic nerve fibers (via the vagus nerve) to decrease heart rate and force of contraction, which is associated with the "rest and digest" state. 

what are the 2 types of receptor ?

chemoreceptors and baroreceptors

chemoreceptors detects what ?

CO2 con.c in the blood

Chemoreceptors where is it found ? 

walls of carotid arteries. 

detects change in pH of blood → caused by increase of CO2 con.c 

baroreceptors detects what ?

Blood pressure

what are the effects of of exercise on heart rate ?

Increase blood CO2→ detect by chemoreceptors→ cardio regulatory centre medulla → Increase in cardioaccelerator nerve  / decrease in vagus nerve → Increase in SAN → Increase heart rate → Increase blood pressure → decreases blood to lungs → decreases in blood CO2.