Lecture 15: The Stress Response Flashcards
Where is the hypothalamus located?
Base of brain and Centre of Limbic region
At the bottom centre of the brain
What is the role of the Hypothalamus?
Releasing and inhibiting hormones, released from axon termini nerve, to control the pituitary
(influences what the anterior pituitary does)
How many hormones does the Hypothalamus release?
9 hormones
all affect the pituitary gland
Where is the pituitary gland located?
2 lobes on a stalk
posterior and anterior
What is the name of the stalk which connects the 2 lobed pituitary gland and the hypothalamus?
infundibulum
What is the Infundibulum?
Stalk which connects the two lobed Pituitary Gland to the Hypothalamus
Blood vessels
Hypophyseal Portal Vein= at the base of the hypothalamus there is a capillary network which go into veins which travel down the infundibulum to a second capillary network in the anterior pituitary gland.
This system allows in the hypothalamus to secrete hormones which travel down down to pituitary capillary network which travel to pituitary gladden and stimulate those cells to do something
What is the role of the Pituitary?
controlling endocrine organs via release into blood stream, and control what those endocrine organs make or don’t make
Hormones travel through a portal vein –> to secondary plexus —> then to pituitary target cells
How many hormones does the Pituitary release?
7 hormones
In combination, what do the Hypothalamus and Pituitary do?
Together regulate growth, development, metabolism, homeostasis Control endocrine system and many of our bodily functions Portal system (Hypophyseal) to allow communication between hypothalamus and Pituitary
What is the Adrenal Gland?
“Ad-Renal” (“ontop” of “Kidney”) Triangular organ sitting on top of the Kidney, in the Retroperitoneal Space
2x Structurally and Functionally distinct areas
-cortex –> 80-90%
-medulla (middle)
Highly Vasculated
Produces Steroid Hormones
What system is the Adrenal Gland closely linked with?
Sympathetic Autonomic Nervous System
What is the Adrenal Medulla similar to?
Modified Ganglion
How does the Adrenal Gland work in synchrony with the Sympathetic Nervous system.
Part of the sympathetic nervous system that is not acting through a ganglion switching station, but is acting directly on the adrenal medulla to cause its cells (modified post ganglionic neurons) to secrete hormones (epinephrine and norepinephrine) into the blood stream, to effect heart(cardiac muscle), Smooth muscle and glands
What are the cells of the Adrenal Medulla?
Modified PostGanglionic “Neuron”
(don’t have long axons extending out, instead have cells completely contained in the adrenal medulla).
and when these cells are stimulated by sympathetic autonomic signals into the bloodstream, release Neurotransmitters/hormones NE and E.
What is the role of the hormones Norepinephrine and Epinephrine?
Sustained action
What is the adrenal medulla stimulated by?
ACh
fromm the Preganglionic Neurons
What hormones are released by the adrenal medulla?
Epinephrine
Norepinephrine
What is the Principal action of the Adrenal Medulla?
Enhances the sympathetic autonomic Alarm response
-Neurotransmitters sent through blood stream to circulate
-affect tissue in a more prolonged way - Slow effect - more Sustained action than the Autonomic System Activation
-this can Enhance and Extend Activation process
several seconds later has an affect
What is the First stage of the Sympathetic Autonomic Flight or Flight Response?
(Inducible) Immediate burst of action
Sympathetic autonomic activation
Sustained through action of Adrenal Medulla - E and NE
What is the Second stage of the Sympathetic Autonomic Resistance Reaction?
Slower (more endocrine manner)
In response to signals from pituitary
Longer lasting
Enhances effected by sympathetic activated cells
Associated with the hypothalamus, pituitary and Adrenal Cortex (cortisol)