Topic 7 – Animal coordination, control and homeostasis Flashcards
(47 cards)
What is homeostasis?
The process of controlling things like temperature and water levels inside the body.
Why does the body need to control temperature?
Increased temperature can speed up an enzyme reaction because the enzymes and substrates have more energy and therefore move about quicker, causing more collisions and quicker reaction. If the temperature is too low, reactions might be too slow.
High temperatures can cause dehydration, heat stroke, and death if untreated
Low temperatures can cause hypothermia, and death if untreated
How does the body detect temperature change?
The hypothalamus has temperature receptors in the dermis of the skin. There is also receptors inside the hypothalamus detect temperature changes in the brain and blood.
What changes happen in the body when there is a temperature change?
- Sweating
- vasodilation (blood vessels near the surface swell to allow more blood near the surface where the heat can radiate out)
- shivering
- Hair stand on end to trap warm air
- vasoconstriction (outer blood vessels restrict to force more blood to vital organs when cold)
How is temperature control an example of negative feedback?
For example, If the body gets too hot, a cooling mechanism like vasodilation occurs, cooling the body. If the body gets too cold, the body shivers or your hair stands up, warming up.
What is heat stroke caused by?
It is an uncontrolled increase in body temperature due to:
Increased body temperature which causes an increase in sweating. This can lead to dehydration which reduces sweating which then allows the core body temperature to rise.
As the body temperature rises, body mechanisms begin
Why is adrenalin produced and what are the effects?
prepares the body for fight or flight by:
- increased heart rate
- increased blood pressure
- increased blood flow to muscles
- increased blood sugar levels by stimulating the liver to turn more glucagon into glucose
how are hormones transported?
dissolved in the blood
what is thermoregulation?
How the body controls your temperature
What is osmoregulation?
The process by which the body controls your body’s water levels.
What are the uses of the liver?
- detoxification
- breaking down unwanted amino acids into urea
What do your kidneys do?
- excrete urine
- filter the blood of unwanted water, salts and urea etc
What is the effect of temperature increase on urine production?
As the temperature increases, the body loses water via sweating. This cause the hypothalamus to crenate as water is lost because it diffuse down the concentration gradient into the blood. As the hypothalamus crenates, it sends a message to the pituitary gland to secrete ADH to the kidneys. The affect of ADH causes the kidneys and the nephron to re absorb more water out of the urine meaning overall there is less urine excreted.
What does crenate mean?
When cells shrivel up due to loss of water
What does lysis mean?
When cells have absorbed too much water and they swell.
What is egestion?
Getting rid of undigested waste
What are nephrons?
Small structures in your kidneys responsible for producing urine. (through filtering the blood)
What processes are performed by the nephron?
- Ultrafiltration
- selective reabsorption
- osmoregulation
What happens at the glomerulus and what is it?
The glomerulus is a small network of capillaries in the nephron in which blood enters at high pressure. The glomerulus then acts like a sponge and filters everything small enough to fit through the capillary walls out into the bowman’s capsule. This means all the large molecules like protein and red blood cells are not filtered out of the blood. [ultrafiltration]
What is the bowman’s capsule and what does it do?
The bowman’s capsule is a capsule surrounding the glomerulus where the smaller substances filtered out of the blood including water, glucose, amino acids, creatinine and urea. Creatinine and urea are waste products tat need to be removed before they become toxic. [filtration]
What is the 1st convoluted tube and what does it do?
Also known as the proximal convoluted tube, it is a part of the nephron where several important substances are reabsorbed. Some of the substances include: water, amino acids and glucose. These are reabsorbed because your body needs them and would be a waste to get rid of them. [ selective reabsorption through active transport]
Some substances like urea are also secreted into the convoluted tube here.
What is the loop of henly and what happens here?
It is part of the nephron where more water is reabsorbed out of the nephron so that more waste products are left in than useful products.
What is the collecting duct and what does it do?
It is a part of the nephron where further reabsorption of water. The amount of water reabsorbed changes because of your body’s osmoregulation. The rest is then sent to your bladder and then excreted out. This mainly contains water , creatinine and urea.
What affect does ADH have on the collecting duct?
It increases the permeability of the collecting duct and therefor increases the amount of water absorbed.
