Homonal Coordination Flashcards
What is the human endocrine system?
Composed of glands that secrete chemicals called hormones into the bloodstream. Blood carries hormones to a target organ where an effect is produced.
Compare the effects of the endocrine system to the effects of the nervous system?
Slower
Act for longer
What organ is blood sugar concentration monitored and controlled by?
Pancreas
What is the pituitary gland?
Master gland in brain
Secretes several hormones
These hormones act on other glands to stimulate the release of other hormones, and bring about effects
What is the negative feedback loop for when blood glucose is too high?
Pancreas releases insulin which moves from the blood into cells
Excess glucose is converted into glycogen in the LIVER and MUSCLE CELLS for storage
Blood glucose falls
What is the negative feedback loop for when blood glucose is too low?
Pancreas releases glucagon
Glycogen converted into glucose and released into blood
Amino acids and fats are broken down
Blood glucose rises
What is diabetes?
Diabetes is a non-communicable disease in which the body either cannot produce or respond to insulin, leading to uncontrolled blood glucose concentrations
What is Type 1 Diabetes (3 things)?
Early onset
Pancreas stops producing sufficient insulin
Commonly treated through insulin injections, also diet control and exercise
What is Type 2 Diabetes (3 things)?
Later onset, often as a result of obesity
Body doesn’t respond to insulin produced
Commonly treated through a carbohydrate-controlled diet and exercise
Maintaining water and nitrogen balance
Water leaves the body through the lungs via exhalation
Water, ions and urea are lost through the skin from sweat
Excess removed by kidneys as urine
Why must levels of water in the body be balanced?
Cells do not function efficiently if they lose or gain too much water
How do the kidneys produce urine?
Filtration of the blood and selective reabsorption of useful substances, such as water, glucose and some ions
How is the water level in the blood controlled?
Hormone ADH
Affects the amount of water absorbed by the kidney tubules
Negative feedback cycle
What is the negative feedback loop for ADH?
Water concentration too high/ low
Pituitary
Less/ more ADH released
Kidney tubules absorb less/ more water
Lots of/ little urine produced
Blood restored to normal
What is dialysis (6 steps)?
Blood temporarily removed from patients body
Filtered through machine
Patients blood passes over dialysis fluid
Dialysis fluid has no urea
Urea and waste products diffuse from high concentration to low concentration
Patients blood returned to body
What is deamination?
Digestion of proteins from food results in excess amino acids
Amino acids are delaminated to form ammonia
Ammonia is toxic so it is immediately converted to urea for safe excretion
What is a negative feedback loop?
Work to maintain a steady state
What is adrenaline?
Produced by adrenal glands in times of stress and fear
Increases heart rate
Boosts delivery of oxygen and glucose to brain and muscles
Prepares the body for fight or flight
Does not involve negative feedback
Why is adrenaline not negative feedback?
Adrenal glands stop producing adrenaline
What is thyroxine?
Produced by thyroid gland
Regulates how quickly your body uses energy and makes proteins = metabolic rate
Important for growth and development
Controlled by negative feedback
What is oestrogen?
Main female reproductive hormone
Produced in the ovary
At puberty, eggs begin to mature, and one is released every 28 days
Causes lining of uterus wall to thicken
Inhibits release of FSH
Stimulates release of LH
What is testosterone?
Main male reproductive hormone
Produced by testes
Stimulates sperm production
What is FSH?
Released by pituitary gland
Causes eggs to mature
Stimulates ovaries to produce oestrogen
What is LH?
Released by pituitary gland
Stimulates the release of mature eggs = ovulation