Mass Transport In Animals Flashcards
What is the haemoglobin?
A group of chemically similar molecules found in many different organisms
- it’s a protein w/ a quarternary structure
Role of Haemoglobin?
To carry oxygen from the lungs around the body
What is a haem group?
- prosthetic group that’s attached to the protein
- it contain an iron ion
Each polypeptide chain in a haemoglobin molecule has what?
A haem group
What makes haemoglobin red?
Iron Ion (Fe+)
Explain disassociation
When red blood cells reach tissue in body (e.g. muscle cells) & oxygen is released from Oxyhaemoglobin
Explain association
When oxygen binds to haemoglobin to form an oxyhemoglobin
What are arteries?
Blood vessels that carry blood away from the heart & into arterioles
What are arterioles?
blood vessels that are smaller arteries
- control blood flow from arteries to capillaries
What are capillaries?
tiny blood vessels that link arterioles to veins
What are veins?
blood vessels that carry blood from capillaries back to heart
Describe the basic layered structure of arteries, arterioles and veins from outside inwards
Tough fibrous outer layer (resists pressure changes from outside & within) Muscle layer (contract & so control the flow of blood) Elastic layer (helps maintain blood pressure by recoiling) Endothelium (smooth to reduce friction & thin to allow diffusion) Lumen (NOT a layer) central cavity of blood vessel through which blood flows
Function of the artery?
- to transport blood rapidly under high pressure from heart to tissue
Structure of artery?
- muscle layer thick compared to veins
- no valves (except in arteries leaving heart)
- overall thick wall
- elastic layer thick compared to veins
How does a thick muscle layer make the artery related to its function?
- means smaller arteries can be constricted & dilated to control volume of blood passing through them
Why does the artery have no valves?
- blood is under high pressure due to heart pumping blood into arteries therefore tends not to flow backwards
How does a thick wall make the artery related to its function?
resists vessel bursting under high pressure
How does a thicker elastic layer than veins make the artery related to its function?
- because it’s important blood pressure in arteries is kept high so blood can reach extremities of the body
- elastic wall stretched at each beat of the heart (systole) then springs back & relaxes (diastole) like an elastic band
- stretching & recoil action helps maintain high pressure & smooth pressure surges created by beating of the heart
What is the endothelium?
- cells that line the interior surface of blood vessels and lymphatic vessels
What is the function of the arterioles?
- carry blood, at low pressure from arteries to capillaries, they also control blood flow between them
Structure of the arterioles?
- muscle layer thicker than in arteries
- elastic layer thinner than in arteries
How does a thin elastic layer make arterioles related to their function?
- because blood pressure is low
How does a thick muscle layer make arteriole related to its function?
- contraction of muscle layer allows constriction of the lumen of the arteriole
- this restricts the blood flow & so controls its movement into capillaries that supply the tissues with blood
Function of veins?
- transport blood slowly, under low pressure from capillaries in tissues to heart