Natalie - Pituitary Gland Flashcards
What are the two parts of the pituitary gland?
The anterior pituitary gland
The posterior pituitary gland
What is the anterior pituitary gland made up of?
Composed of winding cords of three types of epithelial cells flanked by vascular sinusoids
What are the three types of epithelial cells in the anterior pituitary cells
Acidophils
Basophils
Chromophobes
What are acidophils
These have cytoplasm that stains red or orange
What are basophils
Epithelium with cytoplasm that stains a bluish colour
What are chromophobes
Epithelium with cytoplasm that stains very poorly
What is the anterior lobe made of?
(3)
Pars tuberalis
Pars distalis
Pars intermedia
What is the official name for the posterior lobe?
Pars nervosa
What is the posterior lobe/pars nervosa responsible for?
Releases ADH and oxytocin
What is the pars intermedia of the anterior lobe responsible for?
Secreting MSH
What is the pars distalis of the anterior lobe responsible for?
Secretes other pituitary hormones
Why is the pars nervosa/posterior lobe pale staining?
It is nervous tissue
What do the acidophils contain?
They contain small protein hormones
What do protein hormones do?
(2)
Produce growth hormone
Produce prolactin
What do basophils contain?
Glycoprotein hormones
What do glycoprotein hormones do?
(3)
Produce thyroid stimulating hormone (TSH)
Produce luteinizing hormone and follicle-stimulating hormone
Produce adrenocorticotrophic hormone (ACTH)
What do chromophobes do?
(2)
These have minimal or no hormonal content
Many of the chromophobes may be degranulated acidophils or basophils
Write a note on the posterior pituitary
(4)
The bulk of the posterior is composed of largely unmyelinated axons
Contains:
- axons
- glial cells
- and other poorly-defined cells called pituicytes
What hormones do the neurons of the posterior adrenal gland secrete?
(2)
Oxytocin
Anti-diuretic hormone (ADH)
List the contents of the posterior adrenal gland
(3)
Unmyelinated axons
Glial cells
Pituicytes
What is the pituitary gland also called?
Master gland
What controls the pituitary gland?
The hypothalamus
What are the hypothalmic hormones referred to as?
Releasing and inhibiting hormones
Why must we have robust control systems in the body?
To prevent over or under secretion of hypothalmic and anterior pituitary hormones
What does the hypothalamus do to the pituitary gland?
Can switch on or off the pituitary gland
When is prolactin secreted?
In pregnancy or breast feeding
What control does the hypothalamus have over prolactin?
It keeps prolactin switched off other than in pregnancy/breast feeding
List all of the pituitary hormones
(9)
Anterior:
ACTH
TSH
GH
PRL
FSH
LH
MSH
Posterior
oxytocin
ADH
What does ACTH stimulate
Adrenal cortex
What does Thyroid stimulating hormone stimulate?
Thyroid gland
What does Growth hormone stimulate
Can affect multiple tissues
What does prolactin (PRL) stimulate
Mammary glands
What does follicle stimulating hormone stimulate
Testes oor
What does follicle stimulating hormone stimulate
Testes or ovaries
What does Leutenising hormones do?
Stimulates the testes or ovaries
What does MSH stimulate
Melanocytes
What does Oxytocin stimualte
Uterine smooth muscle and mammary glands
Smooth muscle in ductus deferens and prostate gland
What does Antidiuretic hormone stimulate?
Kidneys
What does ADH stimulate
Renin angiotensin aldosterone system
What does TSH trigger in the thyroid?
(3)
Trigger the release of thyroid hormones:
- Thyrotropin releasing hormone (TRH) which promotes release of
- Thyroid stimulating hormone
What does adrenocorticotropic hormone stimulate in the adrenal gland?
Stimulates release of glucocorticoids
Corticotrophin releasing hormone (CRH) cause secretion of ACTH
What does follicle stimulating hormone stimulate?
Stimulates follicle development and oestrogen secretion in females
What hormone promotes release of thyroid stimulating hormone?
Thyrotropin releasing hormone
What hormone promotes the secretion of ACTH
Corticotrophin releasing hormone
What does luteinizing hormone do?
Causes ovulation in females
Androgen production in males
What hormones promotes secretion of FSH and LH?
Gonadotropin releasing hormone (GnRH)
What does prolactin do?
Stimulates development of mammary glands and milk production
What does growth hormone do?
Stimulates cell growth and replication
Describe the pathway of GnRH
(3)
Regulatory hormone = GnRH from hypothalamus
FSH and LH released from pituitary gland
FSH and LH affect ovaries and testes
What affects does prolactin have on the immune function?
(4)
The prolactin receptor is widely expressed by immune cells
Some types of lymphocytes synthesize and secrete prolactin
Prolactin may act as a modulator of immune activity
Prolactin is also classed as a cytokine and is made by macrophages
Comment on the control of prolactin secretion
(2)
Normally switched on -> suppressed by hypothalamus (opposite of all other pituitary hormones)
Increased in some diseases (made by immune cells not pituitary)
Write about the growth hormone (3)
A protein hormone of about 190 amino acids
Secreted by cells in the anterior pituitary
A major participant in control of several complex physiologic processes, including growth and metabolism
Give an example of a cell with growth hormone receptors
Fat cells
What happens when GH bind to GH receptors on fat cells?
(2)
GH leads to break down of triglyceride
And prevent uptake of circulating lipids
What two conditions does a deficiency of growth hormone lead to?
Growth retardation
Dwarfism
What is growth retardation?
Acquired disorder with a deficiency in growth hormone
What is dwarfism
Inherited disease with a deficiency in growth hormone before and after birth
How does excessive secretion of growth hormone affect people
The degree of the symptoms depends on the age of onset: either one of two diseases
What are the two conditions caused by excessive growth hormone
Giantism
Acromegaly
What is giantism
Excessive growth hormone secretion in young children or adolescents
What is acromegaly
Excessive secretion of growth hormone in adults
What happens in acromegaly?
(2)
Some have bone deposits in the face and hands
Photographs are used to monitor changes in patients with this disease
Name two posterior pituitary hormone
Anti-diuretic hormone
Oxytocin
What is another name for anti-diuretic hormone
Vasopressin
ADH affects what two systems
Kidney
Vascular system
How does ADH effect kidney?
ADH promotes re-absorption of water back into the circulation
How does ADH effect the vascular system
Causes constriction of arterioles, which leads to increased arterial -> hence the name vasopressin
What two functions does oxytocin have?
(2)
Stimulation of milk ejection from breast tissue
Stimulation of uterine smooth muscle contraction at birth
