Intro to CVS and general principles Flashcards
What are the functions of the CVS?
- Transport
- defence
- haemostasis
- thermoregulation
What does the CVS transport?
- O2 and substates to cells
- CO2 and metabolites from cells
- hormones and drugs around the body
How does the CVS function as a defence?
- immune cells and molecules in the blood
How does the CVC function in haemostasis?
- blood clotting mechanism (platelets and blood vessel walls)
Hoe does the CVS function in thermoregulation?
- vasodilation/constriction to dissipate/conserve heat
The CVS is also involved in transmission of pressure - where is an example of this?
- like filtration of substrates in the kidneys
What are the components of the CVS?
- heart (pump)
- blood vessels (transport)
- blood
- spleen
The blood is a central components of the CVS what is it made up of?
- solid (cells) including red and white blood cells (45%)
- fluids (plasma) = 55%
What is the spleen and what does it do within the CVS?
- large flat organ caudal to diaphragm
- stores and filters blood
What can horses and dogs do to their spleens?
- the spleen can contract to shunt blood into CVS if required
There are 4 chambers in the mammal heart what are these chambers?
- 2 atria “primer” pumps
- 2 ventricles “power” pumps
How is contraction controlled?
- controlled by an intrinsic pacemaker, and regulated by the autonomic nervous system
Describe heart rate in larger species and smaller species and how it can be affected?
- lower in larger species
- higher in smaller species
- can be breed specific
- can be health related
Describe arteries and what do they do?
- smooth muscle and elastic walls to prevent inferences with blood flow and are able to stretch
- carry blood away from the heart to the body or lungs
Describe capillaries and what do they do?
- very thin walls (endothelial cells only)
- exchange of gases and substrates with tissues
Describe veins and what do they do?
- less muscular than arteries as they carry blood at a lower pressure
- carry blood back to the heart
- also blood reservoirs (blood rests in veins)
Evolutionary the heart is derived from what?
- a simple pulsating pipe
In adult mammals (+ birds and crocs) the heart has developed what?
- septa to divide it into 4 chambers
- separate systemic and pulmonary circuits so the blood doesn’t mix between the two
What is the fish heart like?
- single atrium and ventricle
What is an amphibian heart like?
- 2 atria , 1 ventricle
What are lizard and chelonians hearts like?
- 2 atria, 1 ventricle with incomplete septa
The mammalian heart is a dual circulatory system - where does blood coming from the body enter?
- cranial vena cava
Where does blood coming from the veins enter?
- the pulmonary veins
Where does blood going towards the lungs exit?
- pulmonary arteries