CH 11 The Endocrine System

Where is the pituitary gland located?

located in the sella turcica and suspended from the diencephalon by infundibular stalk

Infundibular Stalk

Connects the pituitary to the hypothalamus, allows yo exert control over the pituitary by blood borne factors

Tropic hormones

some hormones will effect other hormone producing organs

What are the two portions of the pituitary?

• Adenohypophysis

• Neurohypophysis

What are the three regions of the neurohypophysis?

• Pars nervosa

• median eminence

• infundibular stalk

Posterior pituitary

stores hormones produced by the hypothalamus

Hering bodies

secretions stored and released into capillary beds when needed by the body

where does Adenohypophysis arises from?

evagination of the stomodeum

How is the evagination of stomodeum called in amniotes, sharks and bony fishes?

Rathke’s Pouch

What are the three portions of the anterior pituitary?

• pars distalis

• pars intermedia

• pars tuberalis

The anterior pituitary is

the truly endocrine portion of the pituitary producing hormones

Hypothalamic-hypophyseal portal track

chemical factos that travel from the hypothalamus to the pituitary

the hormons of the adenohypophysis are:

• somatropin GH

• Thryotropin TSH

• Adrenocorticotropin ACTH

• prolactin PRL

• Melanocyte

• stimulating hormone MSH

The pineal gland

evagination of the epithalamus that has developed from the median eye

what is the function of the pineal gland?

produces several hormones based on photic stimulation

what hormones are produced by the pineal gland?

Serotonin - normal barin physiology

melatonin - establishment of circadian rhythms

Aminogenic tissue

produces catecholamines and males up the adrenal medulla in mammals

aminogenic tissue is derived from

Ectoderm

Steroidogenic tissue

produces a variety of steroid based hormones and makes up the adrenal cortex

steroidogenic tissue derives from

mesoderm

aminogenic tissues in amniotes

discrete adrenal gland located at cranial aspect of the kidneys

aminogenic cells are also called

Chromaffin cells

aminogenic tissues is controlled by

preganglionic neurons

steroidogenic tissue is controlled by

tropic hormones

Corticosteroids

secretions of the steoidogenic cells

what are the three layers of the cortex?

• zona glomerolusa

• zona fasiculata

• zona reticularis

Zona glomerulosa

superficial layer and produces mineralocorticoids (aldosterone)

Zona fasiculata

middle layer and produces glucocorticoids such as hydrocortisone (cortisol)

Zona reticularis

deepest layer and produces gonadocorticoids

endocrine gonads

testes, ovaries

Interstitial cells of Leydig

produce mal sex hormone testosterone, small clusters of epithelial endocrine cells

Ovary

produces the femla sex hormone estrogen, and progesterone

Estrogen

allows for maintenance of secondary female sexual characteristics and helps regulate reproductive cycle

Progesterone

role in ovulation and maintaining the endometrial thickening for implantation of the embryo

endocrine organs from endoderm

1. thyroid

2. parathyroids

3. ultimobranchial glands

4. thymus

5. pancreas

Thyroid

develops from epithelial cells located pm the floor of the pharynx

Follicular cells

produce thyroxine, arranged into hollow spheres

Thyroglubin

colloidal mass of thyroxine

Parafollicular cells

produces calcitonin in mammals

Calcitonin

regulates blood calcium levels

Parathyroids

produce parathyroid hormone PTH

Parathyroid hormone PTH

helps regulate blood-calcium levels, causes calcium to be removed from bone tissue when calcium is low

Ultimobranchial glands

produce calcitonin, develop from the last pair of pharyngeal pouches

ultimobranchial glands are present in

all gnathostomes except mammals

Thymus

lymphoid organ that in birds and mammals also have endocrine role

what hormone is produced by the thymus in mammals and birds?

Thymosin

Thymosin

stimulate the immune response

Thymus is filled with

lymphocytes and macrophages

Bursa of Fabricus.

evagination of cloaca in young birds, supplements the thymus

Pancreas arises from

endodermal evagination of the foregut

Acinar cells

produce pancreatic juice

Isles of Langerhans

endocrine pancreas arranged as small clusters of cells in mammals

Insulin

causes glucose to be stored as glycogen when glucose levels are high

Glucagon

causes glucose to be released from glycogen into the blood when glucose levels are low