B12 Flashcards
What is the area in the brain that controls your body temperature?
Where is it?
The thermoregulatory centre - monitors temp of the blood
The hypothalamus
How does your body cool itself down?
- Produces more sweat, which cools your skin but also transfers energy to the environment as it evaporates.
- The blood vessels that supply your surface skin capillaries dilate, called VASODILATION, so more blood flows through capillaries, cooling it down.
How does the body keep warm?
• The blood vessels supplying the surface capillaries constrict to reduce the blood at the surface of your skin, called VASOCONSTRICTION, reduces the energy transferred by radiation to the environment
• Less sweat is produced - less energy transferred
• Skeletal muscles contract and relax rapidly ( shivering ), needing desperation, an exothermic raises raises your temp.
- hairs pulled erect to trap insulating layer of air
Two main poisonous waste products?
Urea and Carbon Dioxide
Function of the kidneys?
Important for the homeostasis in the water balance in your body, and excretion
How do the kidneys work?
Filter your blood and remove urea, glucose, mineral ions and water from the blood. The glucose is reabsorbed into the blood by diffusion and active transport, selective reabsorption occurs for mineral ions and water - body takes what it needs.
What do the kidneys do with the excess mineral ions, water and urea?
Produces urine
Methods for treating kidney failure?
- Kidney transplant
* Dialysis - function of kidney carried out artificially.
How does a dialysis machine work?
The fluid contains normal levels of glucose and mineral ions found in a persons blood, excess ions removed by diffusion. Steep concentration gradient kept but the counter flow of the fluid. Moves across partially permeable membrane.
Risks in a kidney transplant?
- Rejection - countered by immunosuppressant drugs - tissues matched as closely as possible
- Very long waiting time
Advantages of dialysis?
- More readily available
* Enables people to live a relatively normal life
Advantages of kidney transplants?
- Free from restrictions
* Eat and drink whatever
Disadvantages of dialysis?
- Special diet
- Expensive
- Eventually can cause serious damage to the body
Urea?
Nitrogenous waste produced by the breakdown of excess amino acids in liver
How does the liver produce urea?
- urea produced when too much protein is eaten or when tissues are worn out and so the extra protein cant be stored and much be broken down
- amino acids cant be used directly as fuel in the body so thy re broken down
-liver removes the amino group from amino acids by process of deamination
forms ammonia which is very toxic, so is converted to urea - rest of amino acid molecule used in respiration or to make other molecules
