Applied anatomy and physiology A level T1

Define atherosclerosis

when arteries harden and narrow, and become blocked with fatty deposits

what is lactic acid

a by-product/toxin of anaerobic respiration

what’s cardiac hypertrophy

when the heart becomes bigger and stronger due to a thickening of the muscular wall

what’s bradycardia 

when there is a decrease in resting heart rate to below 60 bpm 

define the medulla oblongata

the most important part of the brain, because it regulates the processes that keep us alive

define vascular shunting

the redistribution of cardiac output to where oxygen is needed most

define vasoconstriction

the narrowing of the blood vessels/pre-capillary sphincters to reduce blood flow into the capillaries

define vasodilation

the widening of the blood vessels/pre-capillary sphincters to increase blood flow

define myoglobin

a protein found in muscle cells which stores and provides oxygen

define the Bohr shift

when an increase of blood carbon dioxide and a decrease in pH results in a reduction of the affinity of haemoglobin for oxygen

define venous return

the return of blood to the right side of the heart via the vena cava

what is systolic

contracting

what is diastolic

relaxing 

what does myogenic mean

the capacity of the heart to generate its own impulses /contraction

what does the SAN stand for

sinoatrial node

what does the AVN stand for

atrioventricular node

what does the AVN do

relays impulses between the upper and lower sections of the heart

what is the bundle of his 

a collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches of the ventricles 

what are the Purkinje fibres

muscle fibres that conduct impulses in the walls of the ventricles

define sympathetic system

a part of the autonomic nervous system that speeds up heart rate through the accelerator node causing more waves of excitation

define parasympathetic system

part of the autonomic nervous system that decreases heart rate through the Vagus nerve to decrease waves of excitation

define chemoreceptors

detect a rise in C02 levels and detect changes in concentration of oxygen in the blood and pH levels are located in the aorta 

define baroreceptors

detects changes in blood pressure and sends signals to medullar oblongata to regulate heart rate

define proprioceptor 

detects an increase in muscle movement and changes in body position 

define stroke volume

the volume of blood pumped out by the heart ventricles in each contraction

define ejection fraction

the percentage of blood pumped out by the left ventricle per beat

define adrenaline

a stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate

define Atheroma

a fatty deposit found in the inner lining of an artery

define health 

complete physical, mental and social well-being, not merely the absence of disease and infirmity 

define fitness

the ability to meet the demands of the environment

define output

the volume of blood pumped out of the ventricles per minute

define Arterio- venous oxygen difference 

the difference between the pressure of the oxygen in the arteries and veins 

define cardiovascular drift

the increase of HR during taking part in steady state exercise in a warm environment

define Starlings Law

stroke volume increase of due to an increase in venous return

define blood pressure

the force exerted by the blood against the blood vessel wall

describe the process of vascular shunt

increase is in CO2 levels and lactic acid are detected by the chemoreceptors—→ chemoreceptors stimulate the vasomotor which is in the medullar oblongata which signals for redistribution of blood flow—→ vasodilation + vasoconstriction occur in the pre-capillary sphincters which adjust to blood flow into the capillaries 

what are some effects of vascular shunt

• more blood goes to the heart because the heart muscle needs more oxygen to beat faster with more force

• more blood to muscles = oxygen provided for energy

• more blood to skin= more energy needed to cool body down

• blood flow to brain remains constant 

how do baroreceptors detect an INCR or DECR in blood pressure

by detecting the stretching of the arterial wall

what happens if baroreceptors detect an increase of blood pressure

send a message to medulla oblongata where the parasympathetic system sends an impulse to the SA node 

during exercise what do proprioceptors detect and do

detect an increase in muscle movement and send an impulse to medulla oblongata which causes the sympathetic nervous system to be activated 

what stimulates SAN.

sympathetic nervous impulse sends a message to the SAN through the Accelerator nerve. 

what does the SAN do

SAN sends an impulse as waves of excitation across the walls of the atria which causes atrial systole forcing blood into the ventricles as the relax (diastole)

what stimulates the AVN

wave of excitation passes to the AVN

what does the AVN cause

delays the impulse for 0.1s enabling atria to empty and fill, the impulse then passes down the bundle of his which is located in the septum

what happens when the impulse goes to the bundle of his

bundle of his seperate’s into smaller branches called Purkinje fibres which spread around the ventricles and cause them to contract

what does the sympathetic nervous system cause

sends an impulse to the SAN via the accelerator nerve causing the SAN to produce more waves of excitation making the heart contract/beat faster to pump more blood = increase in heart rate 

what does the parasympathetic nervous system cause

sends an impulse to the SAN via the Vagus nerve causing the SAN to produce less waves of excitation causing the heart to slow down= lower heart rate

define haemoglobin

protein found in red blood cells which has an affinity to oxygen

define oxyhaemoglobin

when oxygen combines with haemoglobin

define plasma

fluid substance in the blood used for transportation

what is a type of heart disease

coronary heart disease

what causes coronary heart disease

occurs when the coronary artery becomes blocked or narrow due to build up of fatty acids

what causes a stroke

when blood supply to the part of the brain is cut off

what are some causes of a stroke

• damage to brain cells

• disability 

• brain injury 

what does the brain need a constant supply of and how does it get it

constant supply of oxygenated blood and nutrients to maintain its function which is delivered in the blood

what are the 2 types of stroke

haemorrhagic and ischaemic 

what causes a haemorrhagic stroke 

• when weakened blood vessels supplying brain bursts 

what causes an ischaemic stroke

when a blood clot stops the blood supply

causes of atherosclerosis

High blood pressure, high levels of cholesterol, lack of exercise and smoking

what are the two types of cholesterol

• low density lipoprotein 

• high density lipoprotein 

what does taking part in exercise do to cholesterol

reduces LDL cholesterol and increases HDL cholesterol levels which improved heart health and blood flow 

why is LDL cholesterol bad

it transport cholesterol in the blood to the tissues causing it to build up in arteries

why is HDL cholesterol good

helps remove cholesterol from arteries and break it down, contain a positive antioxidant effect

how is stroke volume effected by physical activity/fitness

• SV increases because venous return(vol of blood returning to heart) increases

• elasticity of cardiac fibres increase so they stretch more providing a greater force of contraction and relaxation of heart