fractured femur homeostasis

Question 1

name and describe the three stages of haemostasis

Answer 1

vascular spasm- due to smooth muscle contraction in vessel walls, reduces blood flow through injured vessels so that a platelet plug can form and coagulation can occur
platelet plug formation- platelet adhesion and aggregation, chemical release brings more platelets to the injured area and promotes vascular spasm
blood clotting- the platelet plug is reinforced with fibrin threads to form a mesh, this mesh traps blood cells and seals the hole until its permanently repaired

Question 2

name the two hormones which act on the kidney to help restore blood volume. explain the action of these two hormones and what impact each will have on blood plasma volume

Answer 2

• aldosterone, increases tubular reabsorption of NA+, water follows by osmosis this increases blood plasma volume
• antidiuretic hormone decreases water loss from collecting ducts so increases blood plasma volume

Question 3

explain two mechanisms related to blood vessels that are used to help increase BP

Answer 3

• constriction of arterioles to increase peripheral vascular resistance, which will increase the blood pressure
• constriction of veins (they provide a loger blood reservoir) an increase in venous returns will increase pre-load and thus increase blood pressure

Question 4

define haematocrit and explain why it is lower than normal

Answer 4

haematocrit is the percentage of blood occupied by the red blood cells
- her blood volume would have been restored by intravenous saline, diluting it so her haematocrit would be lower

Question 5

name and describe the stage of bone healthing what will be occurring for june at this point

Answer 5

formation of a fracture hematoma

• blood leaks from the damaged vessels and form a clot at the sight of injury (6-8hrs)
• near by bone cells die due to lack of nutrients to the tissue at the sight of fracture
• swelling and inflammation occurs
• phagocytosis and osteoclasts remove dead and damaged tissue (can last for several weeks)

Question 6

name the main mineral involved in maintaining bone tissue. name and describe the action of the hormone that will enable increased deposits of this mineral in bone tissue.

Answer 6

calcium Ca2+

- calcitonin stimulates deposits of calcium in bone tissue by inhibiting osteoclast activity

Question 7

name and describe the stage of inflammation what will be occurring at this time for june’s open wound

Answer 7

• vasodilation and increased capillary permeability
• dilation increases blood flow to the damaged area resulting in increased delivery of WBC’S, clotting factors nutrients and removal of waste