The Circulatory System Flashcards
Most important functions of the circulatory system
- Transport O2 + nutrients to all body cells
- Transport O2 + waste away from cells
- Transport hormones to cells
- Maintain PH levels in tissue fluid (acidic)
- Distribute heat to maintain body temp
- Maintain water content and ion concentration in body fluid
- protection against disease causing micro-organisms
- Clotting to prevent blood loss
Features of blood
- Temp: 38 degrees Celsius
- PH: 7.35 - 7.45
- Salinity: 0.9%
- Total body weight: 8%
Volume: - Males: 5 - 6L
- Woman: 4 -5L
Transport of O2
- 3% transported in plasma
- 97% is combined with haemoglobin to become oxyhaemoglobin
Equation for transport of O2
Haemoglobin (Hb) + Oxygen (O2) Oxyhaemoglobin (HbO2)
Blood Plasma
- Plasma is a clear, pale yellow liquid which comprises of 46 - 63% of the whole blood
Consists of: - Water
- Dissolved organic and inorganic solutes (Na and Cl ions, waste)
- Dissolved plasma proteins
Transport of CO2
- 8% dissolved in plasma
- 22% combined with the globin part of haemoglobin molecules
- 70% carried as bicarbonate ion
Equation for transport of CO2
CO2 + H2O Carbonic acid Hydrogen ion + Bicarbonate ion
White blood cells
Leukocyte (granular and agranular)
Red blood cells
Erythrocytes
4 chambers of the heart
- Two thin-walled atria on top
- Two thick-walled ventricles underneath.
Atria
- receives blood
Ventricles
Pumps blood
Veins
Carry blood into the atria
Arteries
Carry blood away from the ventricles
Atrioventricular valves
Prevent back-flow of blood from the ventricles to the atria.
- Left valve has 2 flaps and is called the bicuspid valve
- Right valve has 3 flaps and is called the tricuspid valve
- Held in place by valve tendons that are attached to papillary muscles
Papillary muscles
Contract at the same time as the ventricles, holding the atrioventricular valves closed.
Semi-lunar valves
- 2, found in the arteries
- called the pulmonary and aortic valves
How are the 2 halves of the heart separated?
By the inter-ventricular septum
Right ventricle
- Walls are 3 times thinner than the left
- Produces less force and pressure
- Blood has less far to go (pumps blood to the lungs)
- Less fluid passes from capillaries to the alveoli
Cardiac muscle
- Makes up the heart
- composed of cells called myocytes
Myocytes
- When they receive an electrical impulse they contract together, causing a heartbeat
- Require a lot of oxygen
- Fed by numerous capillaries from 2 coronary arteries
