Topic 6 Flashcards
What are the two roles of the pancreas?
- To secrete digestive enzymes into ducts leading to the SI
- control BGC
What are the islets of Langerhans?
Group of cells that secrete both alpha and beta cells
What happens when BGC is too low
The islet of langerhans will secrete alpha cells that secrete glucagon which will stimulate the break down of glycogen into glucose in order to increase the concentration
What happens when BGC is too high?
The islet of langerhans will secrete beta cells which will decrease the BGC concentration by secreting insulin which stimulates the conversion of glucose into glycogen
Leptin
- secreted by adipose tissue and acts on the hypothalamus to inhibit appetite
- Controlled by food intake and the amount of adipose tissue
- Binds to receptors in the membrane of hypothalamus
What gland is melatonin secreted by?
Pineal gland to control circadian rythms
What are circadian rhythms?
How we have adapted to live in 24 hour cycles
What do circadian rhythms depend on?
Cells in the hypothalamus ( called suprachiasmatic nuclei) and set the daily rhythm
What do high levels of melatonin promote?
Drowsiness and sleep
What do high levels of melatonin promote?
Waking up
What causes jet lag?
The SCN and the pineal gland are continuing to set a circadian rhythm for the timing at the point of departure
What can prevent jet lag?
Melatonin which can be taken orally
What gene on the y chromosome causes gonads to develop as testes and testosterone secretion?
SRY gene
What does the SRY gene code for?
TDF which causes the expression of genes that cause testes development
What is the simplified process of IVF?
Stopping of normal menstraul cycle
Hormone treatment to promote super ovulation
Extraction of multiple eggs
Sperm collected than injected into eggs
Fertilisation occurs in controlled conditions
Implantation of embryos into uterus
Test for pregnancy approx 2 weeks later
What was Aristotle’s theory of sexual reproduction?
The male produces the seed which then becomes the egg when mixed with menstraul blood
How did William Harvey test for Aristotle’s theory?
- examined Deer uteri during mating season
- expected to find eggs immediately after mating but only found signs of development after 2 months
What is type 1 diabetes?
Inability to produce sufficient insulin ( destruction of beta cells)
What is the treatment for type 1 diabetes?
Testing BGC regularly and then injecting insulin when it becomes too high
What is type 2 diabetes?
- The inability to respond to insulin because of a deficiency in insulin receptors
- Major risk factors = fatty diet, lack of exercise, prolonged diabetes
What is the treatment for type 2 diabetes?
Diet changes like eating starchy foods with a low glycemic index as it is digested slowly, eating foods that are high in fibre, eating small amounts regularly than infrequent large amounts
What does thyroxin do?
Secreted by the thyroid gland to regulate metabolic rate and control body temperature
What is hypothyroidism and its effects?
Lack of thyroxin
- weight gain despite apetitie loss
- lack of energy
- depression
How thyroxin increases body ?
cooling triggers increased thyroxin secretion by the thyroid
gland, which stimulates heat production so body temperature rises.
Testosterone
- testes develop testosterone secreting cells
- increases during puberty and stimulates sperm production ( primary characteristic)
- causes penis enlargment, pubic hair, deepening of voice ( secondary characteristic)
