Endocrine system Flashcards
What’s the role of glands in the endocrine system?
Secrete hormones and monitor levels of hormones and chemicals in the body
How do hormones work? (general)
Hormones diffuse to blood stream and then to target cell. Binds to receptor site on target cell, then causes changes within that cell.
How many lobes are there in the pituitary gland? what are they?
3, Anterior, intermediate, posterior.
What’s the structure and function of the anterior pituitary lobe?
It is made from epithelial tissue. It has an indirect blood supply of blood which has come through the hypothalamus. This means it has added hormones which regulate the anterior lobe. These can stimulate it to release more hormones.
What is the structure and function of the posterior pituitary lobe?
It is made up of nervous tissue. Has a big bundle of neurons called Hypothalamohypophyseal. Hormones travel down and are stored at the bottom of the pituitary gland. When hypothalamus decides, sends an impulse down the long word to release hormones.
Which hormones are associated with the anterior pituitary lobe?
Growth hormone
Thyroid
ACTH- cholesterol and steroids
Prolactin- lactation
Gonadotropin - lh, fsh
Which hormones are associated with the posterior pituitary lobe?
Oxytocin- childbirth and lactation
Antidiuretic
What does the pineal gland do?
Secretes melatonin. Also got from sunlight so produces less in the day.
Controlled by day light
Associated with sleep cycle
Where is the thyroid and what is the structure?
In front of larynx
Highly vascular
2 lobes either side of cartilage
Surrounded by fibrous capsule.
What hormones does the thyroid secrete and what hormonal impact does it have?
Produces thyroxine (t3) also tribodinethyvine (t4) and calcitonin
T3,4 inhibit the production of TSH. Make anterior lobe less sensitive to hormones produced by the hypothalamus. Affect metabolic rate of cells
Calcitonin net on bones and kidneys to reduce the calcium levels in the blood. Prevents the calcium being reabsorbed by kidneys.
The posterior of the thyroid houses 4 parathyral glands. These can release their own hormone to increase calcium.
Where is the thymus gland?
It sits between the lungs.
What is the structure and function of the adrenal glands?
They sit at the top of the kidneys. Made up of the adrenal cortex and the adrenal medulla.
The cortex produces adrenalcorticoids.
GlucoCorticoids-Cortisol-body’s response to stress. Production promoted by anterior pituitary
Mineralocorticoids - aldosterone. Water and electrolyte balance.
Sex hormones – predominately male, but in very insignificant amounts
The medulla produces adrenaline, which affects the heart, and noradrenaline, which affects blood vessels.
What is the structure of the pancreas?
Contains cells called langerhans. There are 3 types. Alpha- produce glucagon to increase blood sugar
Beta- Produces insulin to decrease blood sugar.
Delta- somatostantic which means it inhibits the production of both.
What are the pancreatic processes?
Insulin moves glucose from blood stream to cells. It converts glucose into glycogen to be stored in the liver.
promotes the synthesis of fatty acids and the storage of fats.
Decreases the rate of breakdown of glycogen into glucose - glycogenesis
Stops the breakdown of fat into glucose
when blood sugar is low, increases the rate of breakdown of glycogen into glucose - glycogenolysis.
What do the testes do?
Produce testosterone which affects sperm production.
