Topic 7 - Animal Coordination, Control And Homeostasis Flashcards
Hormone
Chemical messengers sent in the blood to a target organ
What produces hormones
Endocrine Glands
Pituitary Gland
Release hormones that act on other glands, referred to as the ‘master gland’
Thyroid Gland
Thyroxine produced which regulates: Metabolism, heart rate and temperature
Ovaries
Oestrogen
Testes
Produce Testosterone controlling puberty and sperm production
Adrenal Gland
Adrenaline
Creates a ‘fight or flight response’
Pancreas
Produce insulin and glucagon regulating glucose
Hormones and Neurones
Neurones:
Fast action
Short duration
Precise areas
Hormones:
Slow Action
Long duration
General areas
Adrenaline
From Adrenal Gland (above kidney)after brain spots a hazard.
- Binds to heart receptors increasing heart rate, increasing blood flow so it receives more glucose and oxygen for respiration.
- Binds to liver receptors breaking down glycogen to glucose,
Negative feedback
Hormones are regulated, if it exceeds its specified amount a response will occur to bring it back to normal.
Metabolism
The rate chemical reactions occur
Thyroxine homeostasis
TOO LOW:
Hypothalamus releases TRH.
TRH stimulates Pituitary to release TSH
TSH stimulates Thyroid to release Thyroxine (and rises)
TOO HIGH:
TRH Inhibited (therefore TSH) reducing production of Thyroxine
TRH
Thyrotropin Releasing Hormone
TSH
Thyroxine Releasing Hormone
Menstruation Cycle 4 stages
Stage 1: Day 1:
Lining on Uterus breaks down and released.
Stage 2: Day 4 - 14:
Uterus lining builds up. For the arrival of the egg.
Stage 3:
Egg develops and released. (OVULATION day 14)
Stage 4: Day 14-28
Lining is maintained until no fertilised egg lands by Day 28.
Treat infertility
Clomifene Therapy, IVF
Clomifene Therapy
If failure to ovulate is the cause.
Clomifene can be used as it contains FSH and LH. This stimulates ovulation and maturation.
IVF (“In Vitro Fertilisation”) example of ART: Assisted Reproductive technology
Eggs are collected from ovaries and fertilised using sperm in a lab. Once an embryo. FSH and LH given.
Hormones and contraceptives
Taking Oestrogen daily can inhibit release of egg due to inhibit of FSH.
Progesterone can be used as it stimulates cervical mucus production which blocks sperm in the cervix.
Eg. ‘Mini pill’, contraceptive injection,
Barriers and contraception
Condoms, diaphragm
Hormone vs barrier
Hormonal more effective.
But may have side-effects.
Don’t prevent STIs
Homeostasis
Maintaining internal environment.
Examples of homeostasis
Osmoregulation, Thermoregulation, Blood Glucose
Negative feedback systems
A response is triggered to counteract the change
Lipids forming
When there is excess glucose for metabolism. It can be stored as glycogen in the liver and muscles. When full lipids form in the tissue.
Glucose levels too high
Insulin released by pancreas. It reaches the liver and causes glucose to be stored as glycogen.
Blood glucose levels too low.
Glucagon released by pancreas. Glucagon causes liver to turn glycogen to glucose.
Type 1 diabetes
Pancreas produces insufficient amounts of insulin.
Meaning the homeostasis is uncontrolled, could cause death.
Treated using Insulin Therapy, once food has been digested an injection into subcutaneous tissue to reduce the rise in sugars.
Also may limit intake of simple carbohydrates and increase exercise to use up glucose.
Type 2 diabetes
Where pancreas produces insufficient or a resistance (doesn’t respond) so sugar levels rise.
Correlated with obesity (BMI 30+ / Waist-to-Hip >1 meaning around abdomen)
Controlled through healthy diet, exercise and weight loss.
Some have medication or Insulin therapy.
Theroregulation
Hypothalamus measures the internal temperature (37C) and communicate with epidermis and derma for external temperatures and trigger a response to counteract.
Thermoregulation, TOO HOT
Erector muscles relax, lie flat.
Sweat secreted from sweat glands through pores. When it evaporates it transfers energy away. Blood vessels close to skin dilate (vasodilation) allowing blood flow near surface to transfer energy to surroundings.
Thermoregulation, TOO COLD
Erector muscles contract. Hair stand on end to trap a layer of air near the surface.
Little sweat.
Blood vessels constrict (vasoconstriction) Less blood flow near surface to minimise energy loss.
Shivering (muscles contract) increasing rate of respiration to transfer more energy.
Osmoregulation
Keep cells functioning properly.
If too high water will osmose into surrounding cells. If too much the cells will burst.
If Too Low water will osmose out of cells into the blood.
Kidneys control how much water is reabsorbed.
Kidneys
1.Removal of urea (excess amino acids from liver)
2.Adjust ion level in blood
3.Adjust water content in blood.
(All done by filtering under pressure.
Kidney process
In Nephrons:
1. Liquid part of blood (water, urea etc) forced out of glomerulus into Bowman capsule at high pressure. Larger molecules can’t pass through so aren’t forced out.
2.All of liquid components flow along the nephron and reabsorbed.
-all glucose selectively absorbed
-ions
-water
All which isn’t absorbed passes through the ureter and out the urethra.
Water content
Controlled by anti-diuretic hormone (ADH)
Brain monitors content and instructs pituitary gland to release ADH.
ADH makes collecting ducts in nephrons to be more permeable. (To reabsorbed)
ADH Water loss
Brain detects
Pituitary gland release ADH.
ADH makes kidney reabsorb.
ADH WATER GAIN
Brain detects.
Pituitary gland produces less ADH.
Kidney reabsorbs Less.
Blood dialysis machine.
Filter for the patient.
Removes waste and keeps substances at correct concentrations.
Dialysis Fluid has the same concentration of salts and glucose so none is removed.
Barriers are permeable to ions and waste but not larger.
Kidney Transplant
Taken from donor. Voluntary or after sudden death.
Must be closely matched and anti-rejection drugs taken to prevent an immune response.
