8.1 Circulatory Systems Flashcards
(35 cards)
What is the difference betweenopen and closed circulatory systems?
In open blood hows through the open body cavity/ blood travels slowly at a low pressure
In closed blood is confined to the blood vessels
Advantages of a closed system?
Maintains blood pressure
Increased flow rate
Flow can be directed/ and diverted
What are single and double circulatory systems?
Single systems are where blood travels through the heart once for each circuit of the body.
Double systems are where t he blood travels through the heart twice for each circuit of the body.
Advantages of the double circulatory system
More oxygen delivered to respiring cells faster
Maintains blood pressure
Pressure can be higher in different parts of the system to prevent capillary damage.
Oxygenated and deoxygenated blood do not mix
Why do mammals need a double closed system?
They have a higher metabolic demand
The diffusion distance to the cell is to great
Oxygen needs to be delivered to cells quicker
Mammals are more active so have higher oxygen demand
Structure of an artery
Thick outer layer of collagen fibres
Thick middle layer of smooth muscle and elastic fibres
Thin layer of endothelium
Function of an artery
Thick wall withstands the high pressure
Collagen fibres gives strength
Smooth muscle constricts lumen
Elastic tissue can stretch and recoil
Endothelium helps to reduce friction
Structure of a vein
Thin outer layer of collagen fibres
Thinner middle layer of smooth muscle and then elastic fibres
Thinner inner layer of endothelium and contain valves
Function of a vein
Large lumen to allow blood flow
Thinner layers of muscle and fibres as they don’t I need to stretch and recoil as much
Values prevent backflow
Thin walls allow muscle to move The blood flow
Structure of a capillary
Thin outer collagen membrane
Thin layer of endothelium
Function of a capillary
Thin walls allow short diffusion distance
Small diameter brings red blood cells as close to the surface as possible for a short diffusion distance.
Smooth endothelium reduces friction
Pores allows easy transfer of substances
What are the fluid types?
- Blood
- Tissue fluid
- Lymph
What are the components of blood?
Plasma, white blood cells & palates and red blood cells (also known as erythocytes)
What is tissue fluid?
It is the liquid that surrounds the cells allowing for transport and diffusion around cells.
What is hydrostatic pressure?
The pressure of the blood due to heart contractions, that forces the tissue fluid out.
What is oncotic pressure?
A net loss of water because of hydrostatic pressure causing a more negative water potential
What happens at the arterial end during tissue fluid formation?
Capillary blood is under high hydrostatic pressure
Hydrostatic pressure is greater than water potential of tissue fluid
Water and dissolved substances are forced out of the capillaries
Large plasma proteins remain in the blood
What happens at the venue end?
There is lower volume of blood, and lower hydrostatic pressure
Water potential in blood is higher than in tissue fluid
Water moves buck into the blood, from the tissue fluid via osmosis.
What is lymph?
Not all tissue fluid passes back into the capillary.
The excess needs to be collected to avoid swelling.
The excess is drained into vessels in the lymphatic system, this fluid is known as lymph.
How does lymph drain?
Lymph moves into the lymph nodes and through the lymphatic drainage system and back the circulatory system
The lymph nodes for drainage are located all over our bodies
What makes up lymph and now is it helpful in our bodies?
Lymph is made up of tissue fluid, lymphocytes and fatty substances.
The lymphocytes are made in the lymph nodes and are white blood cells used within the immune system.
What is the structure of haemoglobin?
A complex protein with 4 subunits
Each of the Ubuntu’s contains the prosthetic group of haem and a polypeptide chain
