Cardiovascular system Flashcards
What is the definition of cardiac output and the difference between submaximal and maximal exercise?
Cardiac output is the amount of blood pumped by the heart per minute. The difference between submaximal and maximal exercise is that submaximal is any activity that doesn’t exceed 85% of maximum heart rate ( CO stays the same ) maximal exercise is where cardiac output increases significantly ( 14-20L for untrained and 25-35L for trained )
What is an anticipatory rise ?
Anticipatory rise is where your heart rate increases even before you begin to exercise. There is caused by an increase in activity of the nervous system causing the adrenal glands to release adrenaline into the bloodstream.
What is vascular shunting and its two processes?
Vascular shunt - redistribution of blood from inactive areas to active areas
Vasoconstriction - Narrowing of the blood vessels to allow less blood to flow through by small muscles in the wall
Vasodilation- Widening of blood vessels allowing more blood to flow through that results from relaxation of the muscular walls of the vessels.
What is the cardiac conduction system?
A group of specialised cardiac muscle cells in the walls of the heart that sends signals to the heart muscle causing it to contract
Describe how the cardiac conduction system causes the heart to contract. (3)
The Sino-atrial node (SAN) (the pace maker of the heart) sends an impulse/ electrical signal through the walls of the atria (1)
- Spreads as a wave of excitation (1)
- This causes atrial systole atria contract (1)
What is the order of the cardiac conduction system ?
1 - Impulse released by medulla oblongata
2- Travels to the sinoatrial node
3- Impulse travels across the atria
4- Travels to the atrioventricular node
5 - Bundle of his
6 - Bundle branches
7 - Purkinje fibres
difference between parasympathetic system and sympathetic system
parasympathetic returns heart rate back to resting level whereas sympathetic stimulates the heart to beat faster by releasing adrenaline which causes blood vessels to constrict to redirect blood where its needed, stimulates the breakdown of glycogen to provide more energy and increases heart rate.
what are the three types of receptors and what do they detect ?
Chemoreceptors- detect increase and decrease in chemical changes e.g carbon dioxide. ^ in CO2 means ^ in HR
Baroreceptors - detect increase or decrease in blood pressure. ^ in BP means v in HR
Proprioceptors - sensory nerve endings located in muscle , tendons and organs that provide information about movement
What is the difference between haemoglobin and myoglobin when transporting oxygen? (2)
Haemoglobin in the blood has red blood cells whereas Myoglobin is located in the muscle.
Myoglobin has a higher affinity for oxygen whereas haemoglobin has a lower affinity for oxygen.
Explain the importance of haemoglobin for a long-distance runner. (3)
important for oxygen transport in the blood / carries oxygen to the muscles
B. Endurance athletes work aerobically
With oxygen too vague
C. Increased red blood cells, increased aerobic capacity / stamina
D. Delays fatigue / delayed OBLA / prevents build-up of lactic acid
Explain how oxygen is taken up by haemoglobin from the lungs and released at the muscle site. (3)
At lungs - high partial pressure of 02 and in the blood - low partial pressure of 02;
Haemoglobin becomes saturated;
At muscles - low partial pressure of Oxygen / 02 and in the blood - high partial pressure of 02;
Hence oxygen dissociates from haemoglobin
What happens if partial pressure is high and if partial pressure is low ?
- If partial pressure is high, haemoglobin will combine with oxygen to form oxyhaemoglobin ( saturated )
- If partial pressure is low haemoglobin will release the oxygen to form deoxyhaemoglobin when haemoglobin releases oxygen it dissociates with oxygen which means its no longer saturated.
What is bohr shift?
Bohr shift is used to measure how chemical activity e.g CO2 lowers PH. The shift is shifted to the right
Explain the causes of the Bohr shift and how it increases oxygen delivery to the working muscles. (3)
- Exercise causes increased CO2 acidity in blood which lowers pH
- Curve shifts to the right
- This leads to more oxygen disassociating from haemoglobin which reduces affinity for oxygen
What are the three venous return mechanism?
Skeletal pump- muscles around the veins expand and contract pressing on the veins causing a pumping effect.
Respiratory pump - change in pressure allows the veins to compress causing blood to be sucked through
Valves - Allows blood to only flow in one direction which is towards the heart and prevents backflow.
