Topic 5 Homeostasis Flashcards
What is the pituitary gland and name examples of hormones it releases.
The master gland in the brain which makes and secrets hormones which travel to target organs in the blood stream. E.g FSH,LH,GH,ADH
Describe the role of ADH ,LH,FSH and GH
ADH-controls water content in blood
LH-Stimulates egg release(ovulation) in females and testosterone production in males.
FSH-Stimulates egg development and oestrogen production in females and sperm production in males.
GH-Speeds up growth and development in children
Describe the process of thermoregulation
The normal body temperature is 37• C,during exercise/sun the body temp increases. This is detected by the hypothalamus, the body sweats to reduce the temp and vasodilation and is back to normal body temp.
During cold weather the normal body temperature decreases which is detected by the hypothalamus, body respires and vasoconstriction to increase body temp to normal level.
Why does water need to be removed from the lungs, kidney or skin and when is it produced?
Produced during respiration, due to osmosis in cells to prevent shrinkage and bursting
Why must carbon dioxide be removed from the lungs and where is it produced?
It is produced during respiration and too much build up in the blood is too acidic therefore toxic when accumulated.
Why must urea be removed from the kidney and where is it produced?
Urea is produced when protein breaks down amino acids and then into urea at the liver, urea is toxic when it builds up.
Reaction time required practical
See book
What is negative feedback?
When the body reverses a change to the control system in order to return to the set level.
What does adrenaline do?
Converts glycogen to glucose for respiration,pupils dilate,increased mental awareness, diverts blood in digestive system to muscles,increases heart/breathing rate
What are the three stages on the kidney?
1:Ultrafiltration-Filters glucose,urea,water and mineral ions into nephron.
2:Selective reabsorption-Reabsorbs all glucose and no urea.Dependent on osmosis for water and diffusion for mineral ions.
3:Collection-Collects urine and moved into bladder in ureter.
Describe the process of maintain normal water content
Too much water is detected by receptors in the brain,pituitary gland stops release of ADH.Less water reabsorption, large volumes of dilute urine.Back to normal water content
Too little water is detected by receptions in brain, pituitary gland releases ADH which causes the kidney tubules to reabsorb more water-smaller volume of concentrated urine.Back to normal water level
Label the kidney,eye etc
See book
Describe the process of blood glucose control.
The normals blood glucose level.Eating increased amount of glucose, which is detected by the pancreas.So insulin is released,which absorbs more glucose and converts the glucose to glycogen in the muscles and liver- background k normals glucose level.
Fasting or exercise decreases glucose level which is detected by the pancreas. Glucagon is released which converts glycogen in the muscles and liver into glucose.Back to normal glucose level.
Advantage and disadvantages of oral contraceptives such as the pill
+:convenient-easily stop taking them when desired
-:Less reliable when incorrectly taken
Advantage and disadvantage of injection/doin patch/implant
-Slow release of progesterone to inhibit maturation and release of eggs
+:Reliable/convenient-dont have to remember to take anything, easy to stop
-:Encourages promiscuity,doesn’t prevent STI’s, invasive to risk of infection
+ & - of barrier methods such as a diaphragm or condom
-> prevents sperm fertilising the egg
+:Prevents STI
-:Must be used every time
Advantages and disadvantages of IUD as contraception
-> Prevents implantation of an embryo by releasing a hormone
+:Long term, don’t have to plan ahead of intercourse
-:Inconvenient removal of its side effects
Advantages and disadvantage of spermicides as contraception which kill sperm
Adv:more effective at killing sperm
Dis: On it’s own would be effective
Adv and disadvantages of surgical methods of contraception
Adv:No risk of pregnancy
Dis: expensive and long procedure
Pros and cons of abstinence as contraception
Pros:works every time
Cons:Dictated when intercourse can occur
What is myopia and hyperopia and how are they treated?
Myopia:Short sightedness where you can see close objects clearly but not distant object. Corrected used concave lens
Hyperopia: Long sightedness which can be corrected by convex lenses
Both caused by light rays not focusing on the retina
Both can be treated with laser eye surgery, contact lenses, replacement lenses
What can auxins be used for?
-Weedkillers
-Rooting powders
-Promoting growth in tissue culture
What is kidney dialysis and what are the pros and cons compared to a kidney transplant?
Kidney dialysis is when a dialysis fluid is given which has the correct concentration of correct substances eg glucose and no urea.The urea diffuses into the kidney fluid and the glucose stays in the blood.
+ Widely available, no risk of rejection
- Inconvenient as it needs doing several times a week, must have a controlled diet unlike with a kidney transplant, doesn’t cure the kidney problem long term
Kidney transplant
+ Can lead regular life (diet, less hospital visits), less expensive long term
- Risk of rejection , must take immunosuppressant drugs which leaves the patient at risk if other diseases, shortage of donors
What happens to excess protein in the diet when it is digested?
Protein is converted into excess amino acids which are deaminated in the liver to form ammonia. Ammonia is toxic so is immediately converted to urea for safe excretion
