Topic 7 Flashcards
What is the Pituitary gland?
The master gland
Secretes hormones into the blood to have an effect on the body or stimulate other gland to produce different hormones
What is the pancreas
Secretes insulin
Controls blood glucose level
Thyroid, what is it
Secretes thyroxine
Controls metabolic rate, heart rate temperature
Adrenal gland
Secretes adrenaline
Involved in the “fight” or “flight” response (the body’s response to stressful situations)
Ovary
Secretes oestrogen
Involved in the menstrual cycle and the developing of female secondary sexual characteristics
Testes
Secretes testosterone
Is involved in the production of sperm and the development of male secondary sexual characteristics
Nervous systems vs hormonal
Blood transports hormone to a target organ vs electrical impluses
Nervous system acts quicker but hormonal systems acts for longer
What is adrenaline?
Adrenaline is a hormone produce by the adrenal glands to prepare the body for a flight or fight response. (Dangerous situation)
Outline effects of adrenaline
Increased heart rate and blood pressure : this allows oxygen to reach the muscles quicker, so we can move out of the path of danger.
Increase blood flow to muscles: blood vessels dilate to allow more blood to reach the muscles. Allowing them to have more oxygen for respiration.
Increase blood sugar levels: the liver is stimulated to break down glycogen into glucose, which muscles use in respiration.
Thyroxine
Thyroxine is a hormone that regulates metabolic rate (how quickly reactions occur).
Thyroxine: Low levels
Low levels of thyroxine stimulate production TRH in hypothalamus
TRH causes the release of TSH from pituitary gland
TSH acts on the thyroid to produce thyroxine
When thyroxine levels have reached the normal level, thyroxine inhibits the release of TRH, which stops the production of TSH
Thyroxine: High levels
Controlled by negative feedback:
When the levels increase, it is detected by receptors in the brain (hypothalamus)
This inhibits the release of TSH
This inhibits the release of thyroxine, so levels of thyroxine fall
Menstrual cycle: FSH
Follicle stimulating hormone (FSH) causes the maturation of an egg in ovary, within a structure called a follicle
Produced in the pituitary gland
Stimulates the ovaries to produce oestrogen
Menstrual cycle: oestrogen
Oestrogen causes the lining of uterus to grow again
Produced in the ovaries
Secretion as stimulated of FSH
Stimulates the production of LH and inhibits the secretion of more FSH
Luteinising hormone: Menstrual cycle
Produced in the pituitary gland
Produced as a result of hormone oestrogen
It releases results in ovulation
Progesterone: Menstrual Cycle
Produced in the ovaries and secreted from the egg follicle
Maintains the lining of uterus, and supports a pregnancy if the eggs is fertilised
Inhibits the release of both FSH and LH
Contraceptive Pill and contraceptive patch : Mixed Pill (oestrogen and Progesterone)
Means oestrogen levels are constantly high, inhibiting FSH so no mature eggs
The lining also stops developing and the mucus in the cervix become thick so sperm cannot move through
IUD/Contraceptive implant
Contraceptive implant release a Continous amount of progesterone, prevents ovaries from releasing the egg and thicken the mucus in cervix so sperm cannot swim.
IUD has same effect, T shaped inserted into the uterus
Non-hormonal methods:
Spermicide, kill or disable sperm but are only 70-80% effective
Condoms and diaphragms (plastic cup which is positioned over the cervix)
Abstaining
Clomiphene therapy:
The main hormones FSH and LH are increased in secretion by hypothalamus due drug. They stimulates maturation and release of the egg.
IVF
The mother is given FSH and LH to encourage the release and maturation of eggs
These are extracted from the mother and fertilised in the lab using sperm
The fertilised eggs develop into embryos and then one or two are inserted in uterus
Pros and Cons of IVF
What is homeostasis?
Homeostasis is the maintenance of a constant internal environment.
Homeostasis factors
Blood glucose concentration
Body temperature
Water levels
What is thermoregulation
The act of keeping internal body temperature constant (37°C)
What is osmoregulation
The process of Maintaining water and salt concentration (osmotic balance) across membranes within the body.
Thermoregulation: too hot
Hypothalamus detects this
Sweat is produced from the sweat glands in the dermis and released onto the surface on the skin (epidermis)
Vasodilation means more blood flow closer to the surface of the skin, resulting in increased energy transfer from the body. Heat dissipates
Thermoregulation: too cold
Hypothalamus detects it
Skeletal Muscles contract rapidly (shivering) to generate heat from respiration
Hairs stand on end to create an insulating layer, trapping warm air
Vasoconstriction means blood does not flow so close to the surface, resulting in less heat lost. Blood redirected to towards vital organs
Insulin
Secreted by the pancreas
Regulates blood glucose levels (if too high loses them)
Insulins binds to cell in the target organs (muscle and liver):
1) glucose to move from the blood into muscle cells
2) excess glucose converted into glycogen which is stored in the liver
Glucagon
Secreted by the pancreas
Regulated blood glucose concentration (if too low increases it)
Glucagon binds to liver cells causing glycogen to be broken down into glucose
Glucose is released into the blood, increasing the blood glucose concentration
Type 1 diabetes
Type 1 diabetes: the pancreas cannot produce enough insulin. This condition is congenital (from birth)
Blood glucose can rise to fatal level, excreted with Urine leaving them thirsty
Advised to decrease simple carbohydrates intake and treat them with insulin injections
Type 2: diabetes
The body cells no longer responds to insulin(resistant to it)
Treatments include reducing number of simple carbohydrates and losing weight and exercising
BMI
Over 30 is obesity
Consider risk factor in type 2 diabetes
Urinary system: kidneys
Urinary system removes impurities and waste products from our blood.
Removal of urea from the blood (urea is produced from in liver due to amino acid break down)
Adjustment of ion levels in the blood
Adjustment of water content of the blood
Route blood takes to be purified:
1) blood containing impurities travels in the renal artery to the kidney
2) the kidney regulate the levels of salt, ions and urea in the blood. Any excess is sent to ureter for excretion, eventually the bladder
3) the purified blood returns to the circulation by way of the renal vein
Structure of the nephron
Nephron:filtration
Occurs in the glomerulus, a collection of capillaries at the Start of the nephron. Urea, water, ions and glucose are small enough to pass out of the capillaries into the bowermans capsule - however proteins and blood cells are too large. Stay in blood stream
Nephron: selective reabsorption
The substances in the bowman’s capsule move into the tubule. At the Proximal convoluted tubule, as much glucose as was lost during ultrafiltration is selective reabsorbed into the blood (pumped via active transport). No glucose left in urine
Water reabsorption
Reabsorption of water and ions - water and ions are reabsorbed at the loops of Henley and collecting duct areas of the tubule.
ADH
Antidiuretic hormone
Produced and released by pituitary gland.
Controls water blood concentration levels, effects the collecting duct
ADH: water concentration of blood too high
Less ADH is secreted from pituitary
Collecting duct becomes less permeable to water
Leads to more water being release in urination (as more remains in tubule, ending up in the ureter)
ADH: water concentration of blood is too low
More ADH is secreted by pituitary gland collecting duct becomes more permeable
Less water remains in tubule more entering blood vessels surrounding.
Less water is released in urination
Kidney failure treatment
Dialysis
Transplants
