The Endocrine System Flashcards
What are the 7 main glands of the endocrine system?
- Pituitary
- Thyroid
- Parathyroid
- Adrenal
- Pancreas
- Ovaries
- Testicles
Which 4 organs have secondary endocrine functions?
- Kidney
- Liver
- Heart
- Gonads
Describe the location and structure of the hypophysis (pituitary gland)
- Size of pea, base of brain
- Two lobes (anterior and posterior)
What controls the pituitary gland?
The hypothalamus (in brain)
How is the pituitary gland and hypothalamus connected?
Via the hypophyseal portal system
The pituitary gland coordinates signals between _____ and ______ glands
hypothalamus
endocrine
The anterior pituitary glands contains which 2 types of cell?
- Adicophil Cells (grows well in acidic environment)
- Basiphil Cells (type of white blood cell)
What are the two acidophil cells found in the anterior pituitary gland and what hormones do they produce?
- Somatotrophs -> growth hormones
- Lactotrophs -> prolactin
What are the three basophil cells found in the anterior pituitary gland and what hormones do they produce?
- Thyrotrophs -> thyroid stimulating hormone (TSH)
- Gonadotrophs -> luteinizing hormone (LT) + follicle stimulating hormone (FSH)
- Corticotrophs -> adrenocorticotropic hormone (ACTH)
What is the function of the posterior pituitary gland
- Stores and secretes two hormones made in the hypothalamus
Which 2 hormones does the posterior pituitary gland store and secrete?
- Vasopressin
- Oxytocin
What is vasopressin?
An anti-diuretic hormone (ADH) that controls water balance
What effect does oxytocin have?
- uterine contraction at birth
- let-down reflex for breast feeding
What is the intermediate lobe of the pituitary gland?
- Thin layer of cells between ant. and post. lobes
What is the function of the intermediate lobe of the pituitary gland?
Produces melanocyte stimulating hormone (MSH)
Which regulates skin and hair pigment
Describe the structure of the thyroid gland
- H-shaped gland in front of neck, below larynx
- Left and right lobes lie either side of trachea
Which two hormones does the thyroid gland produce?
- Thyroxine (T4)
- Triiodothyronine (T3)
What is thyroxine (T4) and how is it processed in the body?
- biologically active hormone which influences cell and tissue activity
- turned into T3 in body
What are the parathyroid gland?
Four pea sized glands behind thyroid gland in neck
Which hormone does the parathyroid gland produce?
Parathyroid hormone
What is the function of the parathyroid hormone?
Regulate calcium levels in blood
If the body senses low levels of calcium or vit-D in the blood, what will happen?
- Parathyroid is secreted by the parathyroid gland
- This causes release of calcium from bones into blood
- And causes kidneys to stop losing calcium in urine, and increase vit D metabolism
Where are the adrenal glands located?
One on top of each kidney
What is the structure of the adrenal glands? (2)
- Outer adrenal cortex
- Inner adrenal medulla
Which 3 types of hormone do the adrenal glands secrete?
- Mineralocorticoids
- Glucocorticoids
- Adrenal androgens
What is the most important mineralcorticoid and what’s it’s function?
- Aldosterone
- maintains salt and water levels (regulating blood pressure)
What is the most important glucocorticoid?
Cortisol
What are the 3 functions of cortisol?
- response to illness and metabolism regulation
- stimulates glucose production (frees up fat and muscle)
- anti-inflammatory effects
What are adrenal androgens?
Male sex hormones
What are the two main adrenal androgens?
- Dehydroepiandrosterone (DHEA)
- Testosterone
What are the 2 main functions of DHEA and testosterone in early life?
- Development of male sex organs
- Female body hair in puberty
What 3 effects does adrenocorticotropic (ACTH) hormone have?
Affects release of:
glucocorticoids
adrenal androgens
aldosterone
Which type of hormone does the adrenal medulla produce?
Catecholamines
What are the 3 catecholamines produced by the adrenal medulla?
- Epinephrine
- Noradrenaline
- Dopamine
What are catecholamines responsible for?
Physiological stress response characteristics
The pancreas is part of which 2 systems?
Endocrine
Digestive
What 2 hormones are produced by islet cells in the pancreas?
- Insulin
- Glucagon
In response to high BG, beta-cells produce:
Insulin
What effect does insulin have?
Charges permeability of cell membranes to allow glucose to enter cells
In response to low BG, alpha-cells produce:
Glucagon
What is the function of glucagon?
Causes liver to release stored glucose into blood
Where is gastrin produced and what’s it’s function?
- Stomach
- Starts acid production by stomach
Where is enterogastrone produced and what’s it’s function?
- Small intestine
- Longer emptying time for stomach after high fat meal
What does secretin do?
Triggers release of digestive enzymes from pancreas
