Key Questions

Question 1

Explain the process of blood clotting?

Answer 1

1. Vasoconstriction: the muscles that have been injured or broken constrict immediately to reduce blood flow and, therefore, blood loss.
2. Platelet plug: damage can cause platelets to stick. They will build up at the injury site, forming a plug. This reduces bleeding.
3. Coagulation: Clotting factors (present in plasma) and fibrin (protein) form a mesh that traps blood cells, platelets and plasma.
4. Clot retraction: the network of threads contractions removing fluid (serum) from the area. The clot then dries, forming a scab over the wound that prevents entry of infecting microorganisms.

Question 2

Identify examples of appendicular and axial skeleton bones?

Answer 2

• Axial- bones around the centre of the body
  examples: vertebrae, sternum, skull
• Appendicular- bones of the upper and lower limbs.
  examples: hands, arms, pelvic glands

Question 3

Describe the different types of joints in the body. GIve an example?

Answer 3

Fibrous (fixed): There is no movement between the bones, the bones are held in place by fibrous tissue. For example the suture of the skull

Cartilaginous joints (can barely move): There is slight or limited movement between bones and movement occurs due to compression of pad of cartilage. For example the joint between the ribs and the sternum.

Synovial joints (swimming): There is a lot of movement in between the bones, within a membrane filled with synovial fluid. For example the joints at the wrist, hip and shoulder.

Question 4

Distinguish between Anabolic and Catabolic reactions?

Answer 4

• Anabolic reactions is when smaller molecules build up to make bigger molecules, using ATP as the energy source
• Catabolic reactions is when larger molecules are broken down into smaller molecules, releasing energy in the process.

Question 5

How is Urea formed

Answer 5

Urea is formed through the process of deamination where the liver breaks down amino acids, ingested protein is converted into amino acids where by which amino group must be excreted from the amino acids, with the production of enzyme by the liver it is converted from ammonia to urea where the body is able excrete through urine