Chapter 5 Flashcards
(23 cards)
What is the cardiovascular system?
- made of?
- functions?
- The cardiovascular system is made up of the heart, blood vessels and the blood
Functions: - Transportation of gases and fuels
- Immunity
- Cellular repair and regrowth
- Thermoregulation
Explain the structure of the heart.
Structure:
- The heart is made up of cardiac muscle
- It has its own blood supply via the coronary arteries
- Situated behind the sternum
- Made up of four chambers: two upper chambers (atria/L and R atrium) and two lower chambers (ventricles L & R)
- The septum divides it into left and right
-Valves in the heart ensure that blood flows in only one direction
What is the function of the heart?
The heart helps to produce blood to be pumped around the body, providing it with oxygen, nutrients and fuel to function.
What is the cardiac cycle? What are its four stages and what do they do?
The cardiac cycle involves the heart filling with blood and then pumping it to th erest of the body via the arterial system.
The four stages of the heartbeat:
- Stage 1 Atrial Diastole: The atria fill with blood returning from the body (deoxygenated) and lungs (oxygenated). From the body it erturns through the vena cava and into the right atrium. From the lungs it returns through the pulmonary vein and into the left atrium of the heart. The heart valves remain shut to allow the blood to flow in the correct direction.
- Stage 2 Ventricular Diastole: Pressure builds up in the atria causing the bicuspid and tricuspid valves to open. This allows the flow of blood into the ventricles, then the valves close again.
- Stage 3 Atrial Systole: The two atriums contract which forces the blood into the ventricles where pressure rises to become more than that in the aorta and pulmonary artery.
- Stage 4 Ventricular Systole: Both the pulmonary and aortic value open at the top of the heart and the ventricles then contract. This forces the blood in the aorta to flow to the rest of the body, or into the pulmonary artery to go the lungs.
What is stroke volume? How is it affected during exercise?
Stroke volume is the amount of blood pumped out of the heart through the aorta with each beat.
- The avergage adult stroke volume is between 70-90mL.
- During exercise, the stroke voolume of a person can increase by 40%. This occurs because the body needs more oxygen supplied to the body to maintain its functioning during exercise.
What is cardiac output? How do you calculate it? How is it affected during exercise?
- Cardiac output (Q) is the amount of blood pumped out of the heart each minute.
- Cardiac output = Stroke volume x Heart rate (Q = SV x HR)
- During exercise, the cardiac output increases due to the increase in both stroke volume and heart rate.
What are the major differences between the cardiovascular systems of males and females?
- The male heart has a greater volume, mass and cardiac output than the female heart. However, the female heart has greater ejection fractions (total amount of blood pumped out with each heartbeat) and heart rate.
- Adult males have approximately 5-6 liters of blood in their bodies and female have approximately 4-5 liters of blood.
What are the functions of the blood?
- Transportation of gases, fuels and minerals
- Protection against dehydration
- Maintaining equilibrium (homeostasis) via enzyme and hormone regulation
- Thermoregulation
- Carrying cells and antibodies to fight infection
- Bringing waste products back to the kidney and liver
(blood components) what are red blood cells
- a blood component
Are produced in bone marrow and contain the protein ‘hemoglobin’ which carries oxygen to the working muscles
(blood components)
what are white blood cells
Produced in bone marrow, lymph tissue and spleen. WBC’s fight infection by absorbing and digesting the disease causing organisms
(blood components)
what are platelets
Also produced in bone marrow and are cells that assist with blood clotting
(blood components)
plasma
Is a clear yellowish fluid that carries nutrients
Made of 90% water which assists preventing dehydration
what are the blood vessels and what do they do?
→ Arteries : have strong elastic walls and carry oxygenated blood away from the heart
→ Veins : carry deoxygenated blood back to the heart
→ Capillaries : Are so small that only single red blood cells can pass through it. Blood flow through capillaries is controlled by precapillary sphincters which can close off the flow of blood to major organs as exercise begins.
what is vasoconstriction?
the stimulation of nerves to the heart and blood vessels to contract or constrict to reduce blood flow to tissue. This occurs during exercise to redirect the blood flow away from non-essential organs and tissues and dirct it to the muscles to provide the working muscles with enough oxygen
what is vasodilation?
the widening or opening of blood vessels. blood from non-essential organs is diverted to working muscles bc the rest of the body constricts while the muscles dilate. This fuels the muscles.
blood pressure
Blood pressure is the force exerted by the blood against the blood vessel walls.
Systolic blood pressure is the pressure in the blood vessels following left ventricular contraction.
Diastolic blood pressure is the pressure in the blood vessels when the heart relaxes.
Blood pressure is measured by a sphygmomanometer and is measured in mmHg.
A normal blood pressure reading
is 120/80 mmHg.
what is thermoregulation?
the keeping of the body’s temperature in a steady state of homeostasis.
The thermoregulatory centre is the hypothalamus in the brain. It monitors temperature through two thermoreceptors:
monitors the temp of blood as blood passes through the brain and the receptors in the skin monitor the external temperature.
what is hypothermia?
Hypothermia is when the core body temperature falls below the minimum temperature required to maintain basic metabolic functioning.
what are hypothermia symptoms?
Shivering (protective response designed to produce heatthrough muscle activity), slow, shallow breathing, confusion, drowsiness, muscular fatigue, exhaustion, slurred speech, loss of co-ordination and a slow, weak pulse.
treatment for hypothermia?
Treatment for Hypothermia;
remove wet clothing, protect from wind chill, remove from windy and/or cold environment, rewarm patient slowly with dry clothes, blankets, sleeping bag, body warmth, offer warm liquids (not alcohol or caffeine)
If patient goes unconscious, call 000, check for pulse
and commence CPR if required.
what is hyperthermia?
hyeprthermia develops when the body gains more heat than it loses.
- increase in sweating
- if dehydrated, surface blood vessels will contrict and stop sweating to conserve blood volume
- this then increases body temperature
- the body’s core temp than rises above normal >37 celcius
stages of hyperthermia
- heat cramps
- Heat cramps can be an early sign of heat illness and dehydration. Cramps are often caused by water loss from the body and imbalances of electrolytes. - heat exhaustion
- Heat exhaustion is caused by excessive loss of body fluids. Symptoms include profuse sweating, cool clammy and pale skin and a rapid, weak pulse. The athlete can also be light-headed and unable to concentrate. - Heat stroke
- Heat stroke is when the core body temperature rises above 40 C. Symptoms include mental confusion, loss of co-ordination, unconsciousness and shock. A rapid pulse and fast breathing are also symptoms.
treatment of hyperthermia
Treatment for these conditions is to cease activity and remove from the environment. Rehydrate with water, sponging with cold water, use of fans, ice vests, wet towels can also assist in bringing the body temperature down.
If patient goes unconscious, call 000, check for pulse and commence CPR if required.
