Chapter 3 (the cardiovascular and respiratory systems) Flashcards
Aerobic
a process taking place in the presence of oxygen
Anaerobic
a process taking place with insufficient oxygen
Deoxygenated blood
blood depleted of oxygen
Oxygentaded blood
Blood saturated/loaded with oxygen
Function of the Respiratory system
Takes in oxygen and removes the carbon dioxide
function of the Heart
receives blood from the lungs and acting as a double pump forces the blood around vascular system to the lungs and body tissues/ muscles
The function of the vascular system
Blood and blood vessels which transport and direct oxygen and carbon dioxide to and from the lungs, heart and body (body tissue/muscles)
Blood
Blood carries all the vital ingredients needed for muscle growth. blood accounts for approximately 8% of total body weight
What is blood made up of?
Blood is made up of blood cells and platelets floating in plasma.
Plasma
Plasma= 55% of blood volume 90% of which is water.
Dissolved in plasma we may find; salt, glucose, fatty acids, blood proteins, waste products, enzymes, hormones, gasses such Carbon dioxide and oxygen
What are the 3 types of blood cells?
- Red blood cells- erythrocytes
- white blood cells- leukocytes
- Platelets
Red blood cells
Biconcave disks just small enough to pass through capillary. They form about 95% of the blood cells. Their main function is to transport oxygen and carbon dioxide. They contain a protein called hemoglobin.
Haemoglobin
is a protein found in red blood cells which has a high affinity for carbon monoxide, carbon dioxide and oxygen.
- can carry 4 molecules of oxygen and transport 97% of the oxygen( remaining 3% is dissolved into plasma)
- haemoglobin can also carry carbon dioxide (20% carried this way)
- highest affinity for carbon monoxide, meaning it will pick this gas up in preference to the other two.
White blood cells
*less than 1% of blood volume
there are 5 different types of leukocytes. The function of the white blood cells are to protect body from bacterial viruses and foreign bodies
Platelets
small cell fragments that help clot the blood. form less than 1% of blood volume,
Blood flow through the heart
- superior and inferior cava- deoxygenated blood enters heart through the superior and inferior cava into the right atrium.
- Pulmonary artery- deoxygenated blood from the the right ventricle pumps the blood through the pulmonary artery to the lungs
- Pulmonary veins (x4)- oxygenated blood from the lungs enters the left atrium via the pulmonary veins
- Aorta- oxygenated blood from the left ventricle is pumped to the whole body through the aorta
Pulmonary
Linked to the lungs
The structure of the heart
- about the size of a clenched fist
- Lies within the Pericardial cavity
- Pericardial cavity forms part of the mediastinum which is part of the thoracic cavity
- 4 types of chambers- 2 top chambers atria, w bottom chambers- ventricles
- close to lungs the right side of heart has little work to do compared with left side
- Left side of the heart is larger
- Hear is surrounded by a closed sac called the pericardium filled with pericardial fluid.
- fluid is needed to reduce effects of friction as heart is continually moving
- heart has 3 layers; Endocardium, myocardium and epicardium
Endocardium
Is the inner layer of the heart, smooth tissue to allow uninterrupted blood flow through the heart.
Myocardium
Is the middle layer of the heart. cardiac muscle tissue, highly specialised, similar to skeletal muscle in appearance single nucleus, containing many mitochondria due to fatigue. cardial cells connected by intercalated discs allowing a coordinated wave of contraction to occur when heart is stimulated.
Epicardium
is the outer layer of the heart, thinner layer of pericardium. made of strong fibrous tissue that helps protect the heart.
cardiac cycle
events of one heart beat
Systemic circulation
-is the circulation of oxygenated blood from the left ventricle to the tissue of the body and return of deoxygenated blood from the tissue of the body to the right atrium.
Pulmonary circulation
is circulation of deoxygenated blood from the right ventricle to the lungs and the return of oxygenated blood from the lungs to the left atrium
Right side of the heart during cardiac cycle
- deoxygenated blood flows into the right atrium from superior and inferior vena cava.
- left and right ventricles relax - blood from atria flow into them
- the atria contracts to ensure the ventricles are completely filled
- the ventricles then contract aortic valves close to prevent back flow) blood pushed out of ventricles
- blood pushed out of ventricles through the semilunar valves into aorta and pulmonary artery
- ventricles relax semilunar valves closed, preventing back flow
- the atria relax and fill again - process repeats.
Left side of the heart during cardiac cycle
- oxygenated blood flows into the left atrium via the pulmonary vein for the lungs.
- left and right ventricles relax - blood from atria flow into them
- the atria contracts to ensure the ventricles are completely filled
- the ventricles then contract aortic valves close to prevent back flow) blood pushed out of ventricles
- blood pushed out of ventricles through the semilunar valves into aorta and pulmonary artery
- ventricles relax semilunar valves closed, preventing back flow
- the atria relax and fill again - process repeats.
Cardiac cycle
- at rest takes 0.8 seconds to complete on cycle.*
the cardiac cycle involves rhythmic contraction and relaxation of the heart muscle. the contraction phase is known as systole and takes approximately 0.3 seconds at rest. The relaxation phase is known as the diastole last roughly around 0.5 seconds at rest.
The conduction system of the heart
- the muscle pump of the heart needs to make it contract
- cardiac muscles need to create a wave-like contraction
- this is so the atria contractract before the ventricle.
4.blood need to flow down from atria to ventricles and then up from ventricles out of aorta and pulmonary artery
5.The heart generates its own electrical impulse - cardiac impulse - wave of contraction is initiated by the sinoatrial node (SA node)- pacemaker in the wall of the left atrium
- SA node controlled by autonomic nervous system atria contraction
- impulse spreads over ventricles from the bottom (apex) of heart.
9.this achieved by atrioventricular (AV) node in the atrioventricular septum - impulse from the atria to AV node down a specialized bundles of nerve tissue - the bundle of his
11 impulse carried to apex of heart, specialised fibers branch into purkinje fibres
12 Purkinje fibers extend upwards and across the ventricles
The process of diastole and systole
Diastole:
1.Both atria fill with blood. aortic valves are closed
2. arterial blood pressure rises above ventricular pressure blood pressure.
3. rising blood pressure forces aortic valves open and blood passively pushes into both ventricles and semilunar valves are closed
Atrial systole
4.Both atria contract actively forcing the remaining blood into the ventricles Semilunar valves remain closed
Ventricular systole
5 both ventricles contract increasing ventricular pressure
6.aortic and pulmonary valves (semilunar) are forced open aortic valves closed
7. blood forced out into aorta and pulmonary artery. at res 40-50% of blood is ejected
8.Diastole of next cardiac cycle begins semilunar valves closed preventing back flow from aorta and pulmonary artery
Heart rate (HR)
the heart rate represents the number of times the heart ventricles beats in one minute. *average resting heart rates are 70-72 bpm’s
How is maximal hear rate calculated?
220 - age = Max HR
Stroke volume
is the volume of blood ejected from ventricles each heart beat. the stroke volume is the difference in the volume of blood in the ventricle before and after ventricular contraction.Average resting sv is approximately 70 ml
End-diastolic volume & End-systolic volume
- (EDV)is the volume of blood in ventricles before contraction (systole) after filling. average 130 ml
- (ESV) volume of blood remaining in the ventricles after contraction (systole)
How to calculate stroke volume?
Stroke volume = end-diastolic volume - end-systolic
How can stroke volume vary?
Blood in:
1. how much blood is being returned to the heart (venous return)
2. how far the ventricles will stretch (remember muscle tissue is elastic)
Blood out:
3)the contractility of ventricles
4) the pressure in the main arteries leading from the heart
Heart rates response to submaximal exercise
- adrenalin released into the body system causing anticipatory rise of heart. the sinoatrial node is stimulated to increase HR
- increase with intensity but reaches a plateau during submaximal work, represent steady state optimal HR for meeting demand for oxygen at the specific intensity
- Decreased rapidly immediately after exercise stops due to a decrease in the demand for oxygen from the working muscles.
4) gradually and more slowly decrease, but still remains elevated towards resting values to allow the body to recover. the oxygen debt.
Heart rates response to maximal exercise
- adrenalin released into the body system causing anticipatory rise of heart. the sinoatrial node is stimulated to increase HR
- increase as exercise intensity increases
- increase but slow down just prior to maximal HR values are reached
- decrease as exercise intensity decreases
- A much slower and longer recovery towards resting values due to greater oxygen debt
Oxygen debt
Additional oxygen consumption during recovery above that usually required when at rest
Cardiac output
- Q=SV x HR
Cardiac output increases directly in line with exercise intensity
-resting values 5L/min
-Maximal values 20-40 l/min (high trained athletes)
resting/submax/max
SV= 60-80 ml/ 80 - 100(ut) 160-200ml(t)/ 100-120ml(ut)160- 200(t)
HR=70-72 bpm/100-130 bpm/ 220 - age
Q= 5l/min / 10 l/mi / 20-40 l/min
Cardiac output response to exercise
1.At onset of exercise q is increased bu the increase in SV & HR.
2.when exercises intensity increases 40-60% of maximal intensity sv begins to plateau.
3 any further increase in Q is due to an increase in HR
Cardiovascular drift
is the gradual decrease in sv and increase in the HR prolonged exercise. An increase in body temperature results in venous return. *Sweating will cause a slight decrease in blood volume
Cardiac control centre
(CCC)
- The medulla obligor in the brain contains the cardiac control centre, which is primary responsible for regulating heart rate via the stimulus of the sinoatrial node.
- the ccc is controlled by the autonomic nervous system (ANS), meaning that it is under involuntary control and consists of sensory and motor nerves from either the sympathetic or parasympathetic nervous system
What are the 3 parts to neral control?
Proprio receptors
Chemoreceptors
Baroreceptors
Proprio receptors
Proprio receptors are receptors found in the muscles, tendons and joints. they inform the CC that motor activity has increased
Chemoreceptors
Chemoreceptors are receptors which are sensitive to the chemical changes, in muscles, aorta and carotid arteries. inform the CC that lactic acid and carbon dioxide levels have increased and oxygen and ph levels have decreased.
Receptors
centre receptors that detect changes in the body.
Baroreceptors
Baroreceptors are sensitive to the stretch within the blood vessel wall, in aorta and carotid arteries. inform the CCC that blood pressure has increased
Sensory nerves
transmit information detected by settler towards the central nervous system (CNS), example chemoreceptors of parts pp O2 to and pp CO2 (pp = partial pressure)
Medulla oblongata
part of the brain (CNS) responsible for regulating respiration, heart rate and blood vessels
Autonomic nervous
system control bodies and voluntary internal functions
Motor nerves
from the central nervous system posse instructions to the body parts =, example muscles, to contract.
Central control centre & autonomic nervous system
CCC & ANS
sympathetic nerves Parasympathetic nerves
increase HR + SV Decrease HR
Via accelerator Via vagus nerve to:
nerve to:
SA NODE
Neural control during exercise
neural information delivered to the CCC. CCC responds by stimulating SA node via the sympathetic ns (cardiac accelerator nerve) this increases HR and SV when exercise stops neural factors gradually reverse Info to CCC Parasympathetic ns (vagus nerve) sends messages for SA node to decrease HR
Hormonal control
Before and during exercise adrenalin is released into the bloodstream from the adrenal glands. Adrenalin directly stimulates the sinoatrial node. this increases Heart rate and the strength of ventricular Contraction. this will therefore increase SV
Intrinsic control
Before and after exercise there are a number of intrinsic factors that affect control of the HR