Circulation (Test Three) Flashcards
Why can sole diffusion only be used in very small, single-celled organisms as means of transporting nutrients, wastes and gases in and out of cells?
Because exchanging materials becomes very inefficient, and only cells less than 1mm in diameter are able to do it efficiently.
Describe the two types of body fluid.
- Intracellular fluid - sum of all fluids inside cells
- Extracellular fluid is the fluid that resides outside cells surrounding them, and provides a buffer for physical and chemical change
What is extracellular fluid further divided into?
- Blood plasma - contained in the blood vessels
- Interstitial fluid - lies between cells in tissues
How is interstitial fluid formed?
It is formed from blood plasma moving into and out of tiny blood vessels called capillaries
All the components of body fluid differ in what way and are mainly made of what?
They differ in their solute concentration and they are composed of mainly water
What is blood called for invertebrates with open circulatory systems?
Hemolymph (blood-fluid)
Invertebrates with closed circulatory systems are able to keep what two thing separate?
The blood in the blood vessels and the interstitial fluid surrounding the cells
Describe the fluid portion of vertebrate blood.
- (Plasma) takes up 55% of blood
- 90% water
- Contains solids like plasma proteins, sugar, antibodies, and hormones
- Also contains dissolved gases like O2 CO2 and N2
Describe the cellular part of vertebrate blood.
- Makes up 45% of blood
- Contains RBC’s, WBC’s and Cell fragments (platelets aka thrombocytes)
Describe the three main plasma proteins.
- Albumins - (60%) keep plasma in osmotic equilibrium
- Globulins - (35%) function by acquiring immunity
- Fibrinogen - (5%) function in part to blood clotting
What is plasma called without the proteins?
Serum
Describe general RBC’s in more detail including their formal name.
- Called Erythrocytes, enormous numbers in blood
- Lack nucleus (for more surface area)
How are RBC’s made in birds and mammals
produced in the bone marrow
How are RBC’s made in other vertebrates?
in the kidney and spleen
What happens when RBC’s die in a human being?
They are removed by macrophages in the liver and the iron is salvaged and recycled, and the heme (broken down hemoglobin) is converted to bilirubin
Describe the first line of defense in hemostasis (blood clotting)
When a blood vessel is damaged, smooth muscle lining the vessel contracts
The special components to clotting are present in which types of organisms?
- in vertebrates
- Larger active invertebrates
Where do platelets come from?
They form in the bone marrow from fragments of large multi-nucleated bone marrow cells.
What do platelets do?
They adhere to any disruption in the inner surface of the blood vessel.
Walk through the specific cascade how blood clotting happens.
When an injury occurs, the platelets adhere to the blood vessel and release blood clotting factors, which with the help of calcium and existing platelet factors allow prothrombin which is contained in the plasma to be converted into its active form thrombin. Once the active thrombin is available, it allows the plasma protein fibrinogen we talked about to form fibrin which will act like a web sealing the area.
What does a complete circulatory system involve?
- Propulsive organ
- Arteries
- Capillaries
- Venous reservoir
- Return system
Describe the circulatory system in fish.
They have a two chambered heart that pumps blood from the heart to the gills to become oxygenated, on its way to the body.
Flows one directionally
Describe circulation in amphibians.
- They have a three chambered heart with two atria and one ventricle
- One atria takes blood to the lungs where gas is exchanged and then returned to the other atria and ventricle where it is mixed and pumped to systematic vascular beds or back to the lung.
- This mixing reduces the efficiency of oxygenation
- Important to recognize that blood exiting the ventricle is diverted, some back to the lung and some to the vascular beds, illustrating the inefficiency.
Describe bird and mammal circulation
- Four chambered heart
- Complete separation of both systematic and pulmonary circuits (oxygenated blood and deoxygenated blood)
