Topic 7 - Animal Coordination, Control and Homeostasis Flashcards
What are hormones?
Chemical messengers
What is a Target Organ?
where the hormone affects
What are Endocrine Glands?
Produce hormones for your body
How does the hormones reach the target organ?
They are released into the blood and carried to the target organ.
What is and what does the pituitary gland do?
This gland produces many hormones that regulate body conditions. Called “master gland” as these hormones act on other glands, directing them to release hormones that bring change.
What is and what do the ovaries do?
Produces oestrogen and progesterone. Ovaries control menstrual cycle.
What is and what do the testes do?
Produces testosterone, which controls puberty and sperm production in males.
What is and what does the pancreas do?
This produces insulin, which is used to regulate the blood glucose level.
What does the adrenal gland do?
Releases adrenaline to prepare the body for a ‘fight’ or ‘flight’ response. Adrenaline binds to specific receptors in the heart. This causes the heart muscle to contract more frequently and with more force, so heart rate and blood pressure increase. This increases the blood flow to the muscles, so the cells receive more oxygen and glucose for increased respiration. Adrenaline also binds to the receptors in the liver. These causes the liver to break down its glycogen stores to release glucose. This increases the blood glucose level, so there’s more glucose in the blood to be transported to the cells.
What does the Thyroid gland do?
Releases thyroxine which plays an important role in regulating metabolic rate - the speed at which chemical reactions occur in the body.
How is the blood thyroxine level kept at the right level?
When the blood thyroxine level is lower than normal, the hypothalamus (a structure in the brain) is stimulated to release thyrotropin releasing hormone (TRH). TRH stimulates the pituitary gland to release thyroid stimulating hormone (TSH). TSH stimulates the thyroid gland to release thyroxine, so the blood thyroxine level rises back towards normal.
When the blood thyroxine level becomes higher than normal, the release of TRH from the hypothalamus inhibited, which reduces the production of TSH so the blood thyroxine level falls.
What is Homeostasis?
Homeostasis is about maintaining a constant internal environment.
What does Homeostasis allow?
Homeostasis allows cells to carry out chemical reactions. Enzymes are very specific and requires constant environment to work properly; temperature, pH and substrate concentration.
What is thermoregulation?
Thermoregulation is the process your body uses to keep its internal temperature steady.
Why is thermoregulation important?
This is important because if the temperature is too low, enzyme activity slows down and if its too high, enzyme may start to denature so they can’t work anymore.
What happens to your body when you are too hot?
Thermoreceptors detect this increase in temperature and send nerve impulses to the hypothalamus. The hypothalamus receives these impulses and send nerve impulses to effectors in the skin. The skin then tries to decrease the temperature.
- Erector muscles relax, hairs lie flat.
- Sweat glands in the dermis release more sweat onto the surface of the epidermis. The sweat evaporates, transferring heat energy from the skin to the environment.
- Blood vessels near the surface widen. This allows more blood to flow near the surface so more energy is transferred. - Vasodilation.
What happens to your body when you are too cold?
Thermoreceptors detect this decrease in temperature and send nerve impulses to the hypothalamus. The hypothalamus receives these impulses and send nerve impulses to effectors in the skin. The skin then tries to increase the temperature.
- Skeletal muscles contract rapidly and we shiver. These contractions need energy from respiration, and some of this is released as heat.
- Nerve impulses are sent to the hair erector muscles in the dermis, which contract. This raises the skin hairs and traps a layer of insulating air next to the skin to keep you warm.
- Very little sweat is produced.
- Blood vessels tighten meaning less blood flows near the surface, which prevents less energy to be lost. - Vasoconstriction.
What is glucose used for?
Glucose is used in respiration for energy.
What is Aerobic respiration?
This is where oxygen is used with glucose to form water + carbon dioxide. This is more useful energy.
What is Anaerobic respiration?
This is where oxygen is not used and only glucose and energy is used to create lactic acid. This is less useful energy.
How is blood glucose levels reduced to the normal when its too high?
Pancreas detects high blood glucose levels and releases insulin into the blood. The insulin is then taken in by the liver and muscle cells which makes the liver and muscle cells turn glucose in and turns into glycogen (glucose molecules stuck together for storage). The glycogen is then released back into the blood. Now the blood glucose levels have reduced.
How is blood glucose levels increased back to the normal when its too low?
Pancreas detects low blood glucose levels and releases glucagon into the blood. The glucagon is then taken in by the liver which makes the liver turn the glycogen into glucose. The glucose is then released back into the blood.
Now the blood glucose levels have reduced.
What is type 1 diabetes?
Type 1 diabetes is where the pancreas doesn’t produce any insulin. This is a condition where your immune system accidentally attacks healthy body tissues (the pancreas) by mistake. Therefore your damaged pancreas is then unable to produce insulin to remove glucose from blood into your cells. Insulin is injected to treat type 1 diabetes.
What is Type 2 diabetes?
This is where not enough insulin is produced meaning that the glucose stays in the blood and isn’t used as a fuel for energy.
What is osmoregulation? What organ are involved?
Osmoregulation is about controlling water content in the blood. The organs involved include the pituitary gland, kidney and bladder.
Why is osmoregulation important?
Water levels and mineral ions in the blood are controlled to keep the concentrations the same inside the cells as around them. This protects cells by stopping too much water from entering or leaving them by osmosis. If body cells lose or gain too much water, they do not function efficiently.
What happens when blood water levels are low?
Osmoreceptors detect change and ADH is released more from the pituitary gland. Then ADH makes the kidney reabsorb more water and blood water levels stabilise.
What happens when blood water levels are high?
Osmoreceptors in the brain detects water gain. The pituitary gland releases less ADH. Less ADH means the kidney reabsorbs less water. Blood water levels stabilise.
What is a kidney?
This organ cleans the blood.
What is a Renal Artery?
This artery sends blood into kidney for cleaning.
What is the vena cava?
Deoxygenated blood from body to heart.
What is the aorta?
Oxygenated blood from heart.
What is the urethra?
Urine goes through this as it exits the body.
What is the bladder?
The bladder stores urine.
What is the renal vein?
Cleared blood back to the heart.
What is the ureter?
This takes urine (formed in kidney) to the bladder.