1.2 Intro to CVRS Flashcards
What are the 5 functions of the cardiovascular system?
Transport of O2 and substrates to cells
Transport of CO2 and metabolites from cells
Distribution of hormones
Defence - white blood cells
Thermoregulation
What are the 4 components of the cardiovascular system?
Heart - pump
Arteries - distribution channels
Microcirculation - exchange of materials
Veins - returns
Describe fish circulation.
Single ciculatory system.
Describe the ampibian heart.
2 atria but 1 ventricle
Describe an amniote heart and circulation.
2 atria and 2 ventricles so have a dual circulatory system.
What is the foramen ovale?
What happens if it fails to close?
It is the hole which connects the atria in a foetus.
If it fails to close the baby has a hole in the heart.
What is the ductus arteriosus?
What happens after birth?
It allows blood in the foetus to bypass the lungs.
It closes off and becomes a ligament.
Which sides are the tricuspid and mitrial valves on?
Tricuspid - right
Mitrial - left
What prevents the valve from turning inside out during contraction?
The papillary muscles through the chordae tendinae.
What are the tricuspid and mitrial valves?
Atrioventriular inlet valves
What are the semilunar valves and where are they found?
Outlet valves
In the pumonary artery and aorta
What do the semilunar valves do?
They prevent backflow into the ventricles at the end of contraction.
What is the cardiac skeleton made of?
Fibrous and connetive tissue - mainly collagen.
Some larger species have a little bit of bone.
What do the coronary arteries do?
They supply the heart with blood via extensive capillarisation.
How many coronary arteries are there and where do they originate?
There are 2, the left and right.
They are found just above the semilunar valve in the aorta.
What is the Vaso Vasorum?
It is a layer found in big ateries which has capillaries to supply the artery with nutrients and oxygen.
What layers do arterioles and venules have?
Endothelium and Tunica Media
What layers do capillaries have?
Only endothelium.
What do resistance vessels do?
They control arterial blood pressure and local blood flow.
How do resistance vessels work?
They increase resistance due to their reduced radius which drops the pressure and the velocity. Also give an increased cross-sectional area for exchange.
What forces are at work in the capillaries?
Oncotic pressure - moves things in
Blood pressure - moves things out
What does the lymphatic system do?
Carries interstitial fluid to the thoracic duct which joins to the Vena Cava.
What is an oedema?
Abnormal accumulation of fluid.
