3.2 Transport in Animals Flashcards
Why do multicellular animals need transport systems?
- high level of activity
- high metabolic rate
- small SA:V ratio
- allows good supply of nutrients to respiring cells
What are the four types of circulatory systems?
Open / Closed / Single / Double
Whats a closed circulatory system?
Where the blood is enclosed in blood vessels. All fish and mammals have a closed system.
What is an Open circulatory system?
-Blood isn’t in closed in blood vessels instead it flows freely through the body cavity.
- Invertebrates have them.
- Unlike closed it doesn’t transport o2
What’s the difference between single and double closed circulatory systems?
Single the blood only passes through the heart once per circuit of the body whereas double the blood passes through the heart twice.
What animal has a double circulatory system?
Mammals and Birds.
What animals have a single circulatory system?
Fish.
What are the benefits of a double circulatory system?
- Blood can be pumped at different pressures in the two systems.
- It’s more efficient gas exchange in capillaries
- Quicker blood flow to tissues so oxygen is delivered to tissues quicker.
What are the different types of blood vessels?
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
What is the structure and function of artery’s?
Function:
- To carry blood away from the heart to the rest of the body at high pressures (oxygenated blood)
Structure:
- Thick walls. Small lumen to maintain high pressures. No valves.
- Folded endothelium (inner lining) allows artery to expand and helps maintain high pressure.
- Elastic tissue in walls to help recoil.
What is the structure and function of the arterioles?
Structure:
- lower amount of elastic fibres lots is smooth muscle
- 3 layers reduce to just 1 near capillaries
Function:
- connect arteries and capillaries
What is the structure and function of the capillaries?
Structure:
- Small lumen and thin one cell thick walls for diffusion. They form capillary beds.
Function
- exchange surface for diffusion
What’s the function of venules?
Connect veins and capillaries
What’s the structure and function of veins
Structure:
- Thin muscle wall and wide lumen so blood flows at lower pressures
- has valves to stop back flow
Function:
- Carry’s blood towards / into the heart under a lower pressure.
Draw out the structure of the heart and label the parts.
Check book/ flash card
Labels:
LV, LA, RV, RA,
Aorta, pulmonary artery
Pulmonary veins and Vena cava
Septum, bundle of his, Apex, purkyne tissue.
Tricuspid AV valve, Bicuspid AV valve
Semi lunar valves.
Chordae tendinae
Coronary artery
SAN
AVN
Left and right side switch
Left side has thicker walls
What is the role of valves in the heart?
They prevent back flow of blood. Make sure blood only flows in one way (unidirectional)
What are the heart walls made of?
Cardiac muscle.
What is special about Cardiac muscle?
It’s myogenic so can contract on its own accord.
What is the order of the cardiac cycle?
Atria systole, Ventricular systole, Diastole.
What happens in atrial systole in the cardiac cycle?
- The atria contract
- The ventricles are relaxed
- As muscles in atria wall contract, they squeeze inwards and increase the pressure in atria. This forces blood out of atria and into ventricles through AV valves.
- Semi lunar valves remain shut as blood pressure in ventricles is lower than blood pressure in arteries.