cardiovascular system Flashcards
What does the sympathetic nervous system do
Stimulates the heart to beat faster
What does the parasympathetic nervous system do
Returns your heart rate to its resting level
What order does an impulse travel in
SAN- atrial systole- AVN- bundle of his- bundle branches- purkinje fibres-ventricular systole
What is the SAN also known as
Sinal atrial node, pace maker
What does the AVN do
Atrial ventricular node, delays cardiac impulse by 0.1s so that the atrium can fully contract and push out all of the blood
Where are chemoreceptors found
They are found in the carotid arteries and aortic arch
What to chemoreceptors detect and react to
Chemical changes
Why is it important for chemoreceptors to detect chemical changes
Excess co2 increases acidity in blood which will denature enzymes and impair physiological functions
What type of impulse sent and where does it go for chemoreceptors and what is the response to this
Sent to sympathetic nervous system, HR will increase so increased removal of lactic acid
Where are baroreceptors found
Aortic arch, carotid sinus heart and pulmonary vessels
What do baroreceptors detect and react to
The increase of blood pressure- this will increase stretch of baroreceptors to decrease heart rate
The decrease of blood pressure- this will decrease the stretch of baroreceptors to increase heart rate
Why is it important for baroreceptors to detect the increase and decrease of blood pressure
To establish a set point for blood pressure so that the HR wont slow down as a decrease in HR means negative performace
What type of impulse will a baroreceptors make and where will it be sent
Any increase or decrease in the sent point will send a signal to the medulla oblongta to increase BP or decrease it again
Where are the propioreceptors found
In muscles, tendons and joints
What do propioreceptors detect and react to
Movement
What type of impulse do propioreceptors make and where are they sent to
Sympathetic impulse send to sinal atrial node to increase HR which will increase O2 delivery to muscles
Stroke volume
The volume of blood pumped out by the ventricles in each contraction
What are the 3 things stroke volume depends on
Venous return, starlings law, contractility of cardiac tissue
What is venous return
The volume of blood returning to the heart via the veins, if VR increases then SV will also increase, the more blood enters the heart so more must be ejected
What is starlings law
During dystole, the more blood that fills the heart the more it needs to stretch, SV will increase as the ventricular volume increases due to the muscle cells stretching t cause a more forceful reaction (think of an elastic band)
What is the contractility of cardiac tissue
The more forceful the heart can contract, the greater the stroke volume can be eg mo farrahs HR is lower because it can contract more as he is a trained professional adult,
Trained adults : 85%
Normal adults: 60%
What is cardiovascular drift
An increase in HR despite the working at the same intensity
Why does cardiovascular drift occur
When we sweat we loose fluid so plasma volume decreases, increasing blood viscosity which increases resistance to blood flow so there is a decrease in stroke volume
What is the pulmonary vascular system
Deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
What is the systemic vascular system
Oxygenate blood to the body from the heart and then the return of deoxygenated blood from the body to the heart
Blood pressure
Force exerted by the blood against the blood vessel wall
What is venous return
The amount of blood returning to the right side of the heart via the vena cava
What are the 3 ways that venous return is overcome by
Skeletal muscle pump
Respiratory pump
Pocket valves
What is skeletal muscle pump
When mucuses contract and relax they can change shape pressing on the veins causes a pumping affect to squeeze blood towards the heart, the changes in pressure compresses beardy veins and assist blood return to the heart
What is respiratory pump
During inspiration and expiration our muscles contract and relax causing pressure changes In the thoracic (chest) and abdominal (stomach) cavities
What is respiratory pump
During inspiration and expiration our muscles contract and relax causing pressure changes In the thoracic (chest) and abdominal (stomach) cavities
Pocket valves
Blood in the veins should flow one direction so valves ensure that a this happens, after blood has passed through they close to prevent the back flow of blood
3 ways pocket valves in venous return help push blood back to body
- gravity (helps blood return to the heart from upper body)
- smooth muscle ( the walls of veins helps squeeze blood back towards the heart) - the suction pump action of the heat
3 ways pocket valves in venous return help push blood back to body
- gravity (helps blood return to the heart from upper body)
- smooth muscle ( the walls of veins helps squeeze blood back towards the heart) - the suction pump action of the heart
What is angina
The pain and discomfort caused by the narrowing of the arteries which leads to a lack of oxygen to the heart, if atheroma breaks off in the coronary artery it can cause a blood clot to block the artery and cause a heart attack
How to prevent heart disease
Regular excerise…
pumps more blood around the body (cardiac hypertrophy)
Increases SV
Improves flexibility of blood vessels which ensures good blood flow, normal pressure and low cholesterol vessels.
What is high blood pressure
and it is an indicator of heart attacks and strokes, its caused by the hardening of the arteries and a reduction in size of the lumen (arteriosclerosis)
(HBP is alsso Known as hypertension)
What does Low density lipoprotein LDL do
Transport cholesterol in the blood to the tissues which increases risk of heart disease
What does HDL do (high density lipoprotein)
Transport excess cholesterol to the liver where its broken down, decrease in heart disease
how does a stroke occur and what does it lead too
Occurs when the blood supply to the brain is cut off
Leads to brain injury, disability and sometimes death
what is oxyhemoglobin disassociation
02 releases to tissues
what is vascular shunt
redirection of blood flow to the most demanding areas.
what is blood pressure and blood flow controlled by
vasomotor in the medulla oblongata
what does the chemoreceptors stimulate
(to do with controlling blood flow)
they stimulate the vasomotor center which will redistribute blood flow through vasodilation and vasoconstriction.
what are 3 factors that shift the bohr curve
blood temp, partial pressure of CO2 and PH
what combines with O2 in the muscle cell and why
Myoglobin, it has a higher affinity for O2 stores
where does myoglobin store the O2
in the mitochondria until it needs to be used by the muscles (used for aerobic exercise)
Where is myoglobin found
slow twitch muscles
associate and disassociate
associate= O2 joins hemoglobin (HB)
disassociate= O2 departs from HB
what happens to the O2 during exercise
3% dissolves into plasma
97% combines to hemoglobin to form oxyhemoglobin
why is redistribution of blood important
-directs more blood to the heart
- ensures blood gets to the skin so you can sweat to regulate body temp
-Increases blood supply to working muscles
-removes waste product (e.g. CO2, lactic acid)
what are pre-capillary sphincters and what do they do
rings of muscles located in opening of capillaries that control weather the blood flows through capillary or not
what happens when the pre-capillary sphincters relax and contract
relax- blood flows through all of the capillary supplying entire tissue
contraction- blood flows straight through, missing capillaries ‘shunting’ blood away from the tissue
what is the Arterio-venous difference
the difference between the O2 content of the arterial blood arriving at the muscles and the venous blood leaving the muscles
what happens to the arterio-venous difference while at rest
its low because muscles do not require much O2
what happens to the arterio-venous difference while exercising
muscles need more O2 so arterio-venous difference is high
what are the 4 valves
Bicuspid valve connecting the left atrium with the left ventricle.
Aortic semilunar valve connecting the left ventricle with the aorta.
Tricuspid valve connecting the right atrium with the right ventricle.
Pulmonary semilunar valve connecting the right ventricle and pulmonary artery
how does the electrical impulse travel
through a waveof excitation
