Endocrine Organs Flashcards
(55 cards)
Serve as effectors to regulate activities of various cells, tissues, and organs in the body
Hormones
Cell Signaling:
Act on adjacent cells or diffuse to nearby target cells that express specific receptors for that particular hormone
hormones released into connective tissue spaces
Paracrine Control
Cell Signaling:
Cells that express receptors for hormones they secrete
Autocrine Control
Two major integration and control system of the body
1) endocrine system
2) nervous system
Communicate through transmission of neural impulses along nerve cell processes and the discharge of neurotransmitter
Nervous System
Communicate through hormones
Endocrine System
Nervous vs. Endocrine
- resspond rapidly and precisely to stimuli
- rsponses are consciously generated
Nervous System
Nervous vs. Endocrine
- responds more slowly and more diffusely
- long lasting effect of responses
- responses are unconsciously generated
Endocrine System
Master organ of the endocrine system - Plays a central role in number of regulatory feedback mechanism
Pituitary gland
Pitutary gland characteristics:
1) size
2) shape
3) location
4) weight
1) small pea sized
2) ovoid
3) centrally at base of brain; sits on the sella turcica of the sphenoid bone
4) Male - 0.5g; Female - 1.5g
Connected to the hypothalamus by a short stalk aka infundibulum
The pituitary gland consists of 2 functional compartments namely:
1) Anterior lobe/ Adenohypophysis (glandular epithelial tissue)
2) Posterior lobe/ Neurohypophysis (neural secretory tissue)
Pituitary Gland
Pituitary compartment that is more cellular and produces hormone
adenohypophysis
the neurohypophysis does not produce hormone but instead stores hormone produced by the hypothalamus
Pituitary Gland
3 Subparts of the adenohypophysis:
1) Pars distalis
2) Pars tuberalis - pars infundibularis
3) Pars intermedia
What are tropic hormones?
Hormones that regulate the hormone secretion of other cells in different endocrine glands throughout the body
Pituitary Gland
Enumerate the hormones of the anterior lobe of the pituitary gland
Tropic Hormones
- adrenocorticotropic hormone (ACTH)
- Thyroid stimulating (thyrotropic) hormone (TSH or thyrotropin)
- follicle stimulating hormone (FSH)
- lutenizing hormone (LH)
Hormones that act directly on the target organ - not endocrine organ
- growth hormone (GH) or somatotropin
- Prolactin (PRL)
Pituitary Gland
Enumerate the 5 functional cells or the anterior lobe - pars distalis
1) somatotrophs (GH cells)
2) Lactotropes/ Mammotropes (PRL cells)
3) corticotropes (ACTH cells)
4) gonadotropes (FSH and LH cells)
5) Thyrotropes (TSH cells)
Types of secretory epithelial cells based on staining
(1) Chromophils
(2) Chromophobes
Chromophils are further classified into: acidophils and basophils
Pituitary Gland
Somatotropin (GH) affects practically all cells
What disease is due to the hypersecretion of somatotropin
- Gigantism
- Acromegaly
Pituitary Gland
Summary of the staining characteristics of adenohypophysis cells
1. Somatotrope
2. Lactotrope
3. Corticotrope
3. Gonadotrope
4. Thyrotrope
Pituitary Gland
Hormones of the Anterior lobe of the Pituitary gland
Somatotropin is stimulated by (1) and inhibited by (2)
(1) growth hormone releasing hormone (GHRH) & Ghrelin
(2) Somatostain - secreted by the hypothalamus and the pancreas
Lactotrope secretion and its function
Prolactin
stimulate the growth and activity of the mammary glands during lactation and pregnancy
Stimulated by: Thyrotropin releasing hormone (TRH) and vasoactive inhibitory peptide
Inhibited by: Dopamine
Lactotrope secretion and its function
Prolactin
stimulate the growth and activity of the mammary glands during lactation and pregnancy
Stimulated by: Thyrotropin releasing hormone (TRH) and vasoactive inhibitory peptide
Inhibited by: Dopamine
Corticotrope secretion
Adrenocorticotropic hormone (ACTH)
& pro-opiomelanocortin (POMC)
Regulated by: corticotropin releasing hormone (CRH) by the hypothalamus
