HYPOTHALAMUS AND PITUITARY GLAND

a cell, a tissue or an organ which secrete useful chemical compounds required for particular function

gland

types of glands

1. endocrine

2. exocrine

those glands which lack ducts and pass their secretion into blood for transport to site of action

endocrine

these secretion are called as HORMONES

endocrine

example of endocrine glands

1. pituitary

2. thyroid

3. adrenal

4. parathyroid

these glands have ducts for discharging their secretion

exocrine

example of exocrine

1. sweat

2. salivary

3. gastric gland

4. liver

System formed by ductless glands which secretes chemical substances called hormones

endocrine system

Endocrine glands release hormones directly into the

blood

are minute chemical messengers throwninto the blood to act on target organs

hormones

can pick up the specific hormone capable of acting in the cell

receptor

contains several groups of NEURO-SECRETORY CELLS called NUCLEI which PRODUCE HORMONES

hypothalamus

these hormones regulate the SYNTHESIS and SECRETION of PITUITARY HORMONES

hypothalamus

hypothalamus

1. releasing hormones

2. inhibiting hormones

gonadotrophin releasing hormone (GnRH); stimulates the PITUITARY SYNTHESIS and release of GOANDOTROPHINS (FSH and LH)

HYPOTHALAMUS: RELEASING HORMONES (stimulate secretion of pituitary hormones)

SOMATOSTATIN from the HYPOTHALAMUS inhibits the release of GROWTH HORMONE from the PITUITARY

HYPOTHALAMUS: INIHIBITING HORMONE; INHIBIT SECRETION OF PITUITARY HORMONES

From the HYPOTHALAMUS inhibits the release of GROWTH HORMONE from the PITUITARY

somatostatin

where does the hypothalamus located

• diencephalon of the brain

• anterior and inferior to the thalamus

function part of hypothalamus

• neural function

• endocrine function

where does hypothalamus suspended

infundibulum or pituitary stalk

pituitary gland

1. adenohypophysis

2. neurohypophysis

adenohypophysis

1. pars distalis

2. pars intermedia

neurohypophysis

pars nervosa

ADENOHYPOPHYSIS - pars distalis (anterior pituitary) produces

1. growth hormone (GH)

2. prolactin (PRL)

3. thyroid stimulating hormone (TSH)

4. adrenocorticotrophic hormone (ACTH)

5. luteinizing hormone (LH)

6. follicle stimulating hormone

ADENOHYPOPHYSIS - pars intermedia produces

1. melanocyte stimulating hormone (MSH)

NEUROHYPOPHYSIS - pars nervosa (posterior pituitary) STORES and RELEASES 2 hormones

1. oxytocin

2. vasopressin (AD)

stimulates ANDROGEN PRODUCTION by gonads

luteinizing hormone (LH)

stimulate GAMETE PRODUCTION in gonads

follicle-stimulating hormone

stimulates HORMONE RELEASE by ANDRENAL CORTEX

adrenocorticotropic hormone

does not produce hormones, but rather stores and secretes hormones produced by the hypothalamus.

posterior pituitary gland

produce the hormone oxytocin, whereas the supraoptic nuclei produce ADH.

paraventricular nuclei

stimulates uterine contractions and dilation of the cervix

Oxytocin

continually released throughout childbirth through a positive feedback mechanism.

Oxytocin

prompts uterine contractions that push the fetal head toward the cervix.

Oxytocin

This increases the intensity and effectiveness of uterine contractions and prompts additional dilation of the cervix. The feedback loop continues until birth

Oxytocin

BUT continues to play a role in maternal and newborn health

Oxytocin

is necessary for the milk ejection reflex (commonly referred to as “let-down”)

Oxytocin

is thought to contribute to parent–newborn bonding, known as attachment.

Oxytocin

also thought to be involved in feelings of love and closeness, as well as in the sexual response.

Oxytocin

Blood osmolarity is constantly monitored by osmoreceptors—specialized cells within the hypothalamus that are particularly sensitive to the concentration of sodium ions and other solutes.

ADH

In response to high blood osmolarity, which can occur during dehydration or following a very salty meal, the osmoreceptors signal the posterior pituitary to

ADH

is controlled by a negative feedback loop.

ADH

As a result, less water is reabsorbed from the urine filtrate.

ADH

consumption inhibits the release of ADH, resulting in increased urine production that can eventually lead to dehydration and a hangover

alcohol

s characterized by chronic underproduction of ADH that causes chronic dehydration.

diabetes insipidus

can occur in severe cases of diabetes insipidus

electrolyte imbalance