6.6 hormones, homeostasis & reproduction Flashcards
Endocrine system
Hypothalamus
Pineal gland
Pituitary galnd
Thyroid gland
Parathyroid
Thymus
Adrenal glands
Pancrease
Ovary & Testes
Pancreas
Releases Glucagon and Insulin into the blood stream to regulate blood sugar levels.
Insulin
Produced by beta cells in the pancreas.
Blood takes it to the liver through circulatory system.
Lowers blood sugar levels by signaling liver cells to store more glucose as glucogen
Glucagon
Produced by Aplha cells in pancreas
Raise blood sugar levels by stimulating Liver cells and muscles to realease and hydrolyze gluogen to glucose.
Liver breaks glycogen into glucose back into blood stream
Type 1 diabetes
Early on-set
Can’t produce sufficient quantities of insulin
Autoimmune disease, destruction of beta cells
Treatment:
Injecting insulin when blood duger levels are too high
Type 2 Diabetes
Late-onset
Deficiency of insulin receptors or glucose transporters on target cells
Risk factors:
Sugary & fatty diets, obesity, lack of exercise, genetic factors
Treatment:
Adjusting diet, control of sugary foods, exercise, weight loss
Thyroxin
Hormone produced by thyroid gland.
Regulate body temp & Metabolic rate
Leptin
Hormone secreted by cells in adipose tissue (fat).
Tells hypothalamus to inhibit appetite.
Makes you eat less
Melatonin
Hormone secreted by pineal gland.
Suprachiasmatic nuclei cells control secretion.
Ganglion cells in the retina detect blue light, preventing release of melatonin.
Jet lag with time zones makes it hard for the body to understand when to produce melatonin.
SRY gene
A gene on Y chromosome, causes gonads to produce testes.
Testes produce testosterone in 15th week of pregnancy.
Puberty secretes more testosterone & sperm production
Estrogen & Progestrone from birth
SRY gene is not present bc. there is no Y chromosome
Gonads develop as ovaries
Estrogen and progestrone are secreted by motheres ovaries & placenta.
During puberty, estrogen and progestrone is secreted more, causing breasts and menstration
Structure of the Male Reproductive System
Structure of the Female Reproductive System
Menstruation
Implantation of egg occurs when the endometrium is highly vascular
If no implantation occurs, the endometrium is shed (menstruation)
How is the menstruation cycle controlled
Hypothalamus
Produces GnRH (gonadotrophin releasing hormone)
Released into the pituitary gland, causing it to release FSH (Follicle Stimulating Hormone) and LH (Leutinising Hormone)
Travels to the ovaries to cause increased production of estrogen -> through the bloodstream to the endometrium of the uterus to become vascular
Positive feedback loop.
Progestrone
Inhibit GnRH production in the hypothalamus
Produced by Corpus Luteum to prevent another mentruation cycle
If pregnancy occurs, the placenta then produces progesterone
In Vitro Fertilisation (IVF)
William Harvey’s investigation of sexual reproduction in deer
- William Harvey failed to solve the mystery of sexual reproduction because effective microscopes were not available when he was working, so fusion of gametes and subsequent embryo development remained undiscovered.
