Unit 2: Book 2 Flashcards
What is the heart? 💚
A muscular pump
What is blood?💚
Fluid connective tissue
What are the blood vessels ?💚
Arteries, veins and capillaries
Where does blood flow away from the heart in?💚
The arteries
Where does the blood flow back to the heart in?💚
The veins
What happens when the blood travels away from the heart💚
There is a decrease in blood pressure
What supplies oxygenated blood to all parts of the body💚
Arterial branches of the aorta
Where does deoxygenated blood leave the organs💚
Through the veins
What returns the blood to the heart💚
The vena cava
What provides the heart with oxygenated blood💚
The coronary artery
What returns deoxygenated blood to the circulation💚
The coronary vein
What is different about the pulmonary system💚
The pulmonary artery carries deoxygenated blood and the pulmonary vein carries oxygenated blood
What does the hepatic portal vein do🧡
Carries blood from the capillary bed of the intestine to the capillary bed of the liver
What is the lumen❤️
The central cavity of a blood vessel
What is the lumen lined with💚
The endothelium
What are thicker, veins or arteries💚
Arteries have a thick middle layer with more elastic fibres
What do elastic fibres do💚
Enable the artery to pulsate , stretch and recoil, thereby accommodating the surge of blood after each contraction of the heart
What causes vasodilation🧡
The contraction or relaxation of the smooth muscle
What is vasodilation🧡
The circular muscle in the arteriole wall is relaxed and the lumen is wider
What is vasoconstriction🧡
The circular muscles are contracted and the lumen is narrower
Where do veins carry blood❤️
Back into the heart
Are veins thinner than arteries, and why💚
Yes, as the outer muscular layer of the connecting tissue containing layers of elastic fibres in the vein are thinner than those in artery because blood flows along a vein at low pressure
What lumen is wider, vein or artery💚
Vein
Why are valves present in veins💚
To prevent the back flow or blood
How is blood transported from the arterioles to venules💚
The capillaries
What takes places through the capillary walls❤️
All exchange of substances between blood and living tissue
What are capillary walls composed of💚
Endothelium
What is plasma💚
A watery yellow fluid containing dissolved substances such as glucose, amino acids, blood cells, platelets and plasma proteins
Is blood arriving at the arteriole end of a capillary bed at a higher or lower pressure than blood in the capillaries💚
Higher
What is pressure filtration🧡
As blood is forced into the narrow capillaries, it undergoes pressure filtration
What does tissue fluid contain🧡
A high concentration of dissolved food, oxygen and other useful substances
Where does much of the tissue fluid return to❤️
In the capillaries at the venule end of the capillary bed
What does tissue fluid lack❤️
Plasma proteins, which are too large to be filtered through the capillary walls, so it has a higher water concentration then the blood plasma
Where are some of the tissue fluid absorbed by🧡
Thin walled lymphatic vessels
What is lymph💚
When the tissue fluid is in the lymphatic vessel it is called lymph
What is flow of lymph brought
about by💚
The vessels being compressed when muscles contract during breathing or body movement
What do larger lymph vessels have💚
Valves to prevent back flow
how do lymph vessels return their contents to the blood🧡
Via two lymphatic ducts
What is the heart divided into and what are they called💚
4 chambers, two atria and two ventricles
What does the right atrium receive and where does it come from🧡
Deoxygenated blood from all parts of the body via the Vena cava
What passes into the right ventricle💚
Deoxygenated blood passes into the right ventricle before pressing the heart the pulmonary artery
What do valves do💚
Prevent the backflow of blood
What valves are present at the origins of the pulmonary artery and the aorta💚
Semi lunar
What is cardiac output🧡
The volume of blood out of a ventricle per minute
What is heart rate💚
This is the number of heart contracts per minute which correspond to the pulse rate
What is stroke volume🧡
This is the volume expenses by each ventricle on contraction
How do you calculate the cardiac output💚
CO= HR (heart rate) x SV (stroke volume)
If a person is fit will the quantity of cardiac muscle present in their heart wall be greater or smaller💚
Greater
Is a fit persons stroke volume greater or smaller💚
Greater
What is the cardiac cycle💚
The pattern of contraction and relaxation during one complete heart beat
What is systole❤️
Contraction
What is diastole💚
Relaxation, during diastole, the god returning to the atria flows into the ventricles
What is the average length of one cardiac cycle
0.8 seconds
What happens when atrial pressure exceeds the pressure in the ventricles
The AV valves are pushed open and the blood enters the ventricles