B12 Homeostasis
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What happens when your body is at a high temperature
Enzymes denature and active site changes shape You begin to sweat, this evaporates, you loose water, therefore your body has less fluid, no more sweat can be produced, coma, death Hyperthermia
What happens when your body is at a low temperature
Molecules have less kinetic energy so no enzyme substrate complex Which means chemical reaction cant happen Shivering-Movement creates some kinetic energy Signs-Drowsy, blue lips, slurred speech, greyish lips Hypothermia
How does your body control temperature
The temperature is sensed by the thermoregulatory centre in the hypothalamus and by temperature receptors in the skin The hypothalamus coordinates a response and sends electrical impulses to effectors to return the body to 37
How does sweating cool you down
When sweat evaporates from your body, it takes heat energy from your body to turn water into vapour
How does the skin help cool you down
Hair erector muscles relax and hairs lie flat so less air is trapped near the skins surface Swat glands make sweat which evaporates Blood vessels near the skin widen so more blood is nearer to the surface which increases heat loss through radiation
How does the skin help keep you warm
Hair erector muscles contract and make the hair stand upright which traps warm air close to the surface Sweat glands stop making sweat Blood vessels get narrower so less blood gets near to the surface and less heat is lost through radiation
What are the 2 main poisonous waste products in the body
Carbon dioxide Urea
Why must carbon dioxide be removed from the body
Dissolved carbon dioxide produces an acidic solution which would affect the working of all the enzymes in your cells
How is carbon dioxide removed from the body
Carbon dioxide diffuses out of your cells into your blood down the concentration gradient It diffuses from the blood into the air in the alveoli in your lungs The air containing the carbon dioxide is removed when you exhale
What is urea
The nitrogenous waste product from the breakdown of amino acids in your liver When you eat more protein than you need or your tissues are worn out the extra protein cannot be stored and must be broken down
How is urea removed from the body
It passes from your liver cells into your blood It is filtered out of the blood by your kidneys and passed out of the body in urine
What does your body have no control over in regards to removing waste
Water leaves the lungs every time you breathe Water, mineral ions and urea are lost through sweat
What does your body have control over in regards to removing waste
Urea, excess water and mineral ions are removed from the body via the kidneys, then excreted in the urine. This process is very tightly regulated.
What are the 4 useful and 2 toxic substances in the blood
Useful: Glucose Amino Acids Mineral Ions Water Toxic: Urea Carbon Dioxide
How does a healthy kidney work
The blood with useful substances is carried to the kidney tubule by the renal artery The blood is filtered All the glucose is reabsorbed by active transport The dissolved ion needed are also reabsorbed by active transport If the body needs water it is reabsorbed-Controlled by ADH Urine, made up of urea and excess water and ions the body doesn’t need, is transported to the bladder
What is ADH
Anti diuretic Hormone-Secreted by the pituitary gland Works by negative feedback maintaining blood water balance Pituitary gland detects levels of solutes in blood plasma If blood is concentrated kidneys will absorb more water If blood is too dilute kidneys will absorb less water