Unit 2: Homeostasis Flashcards
Exocrine Gland Vs. Endocrine Gland
The endocrine gland sends hormones into the blood stream/ interstitial fluid space, whereas the exocrine glands send things outside of the body into the “lumen”
Examples of exocrine glands
Tear ducts, digestive juices into the stomach
What is the Star Trek example of the relationship between the hypothalamus and the pituitary gland?
The Hypothalamus is the captain, whereas the pituitary gland is the first officer.
How does the endocrine system signal broadcast relate to cells?
Cells have specific receptors that “tune in” to different broadcasts by the endocrine system.
Three types of hormones:
Peptide hormones, steroid hormones, and amine hormones
Peptide Hormone Stages{pre…]
Preprohormone is turned into pro hormone during the synthesis stage. Proteolytic enzymes then break down the pro hormone into the hormone and the pro fragments during the packaging.
What is the usual destination for peptide hormones?
They bind to receptors on target cells that begin second messenger pathways.
Steroids: hydrophilic/lipophilic
lipophilic
Steroid Hormone Structure and Secretion: Where do Steroids come from?
Derived from cholesterol. Peptide hormone attaches to receptor that turns cholesterol into steroid hormone.
How do steroids [hydrophobic] travel through the water?
Globulins help steroids move through the water
Inner and outer Adrenal …
Adrenal Medulla: inner; Adrenal Cortex: Outer
What are the two major thyroid hormones?
T3 and T4
What are catecholamines?
Derived from tyrosine via enzymatic reactions; norepinephrine, epinephrine
Define permissiveness
When one hormones “permits” another hormone to elicit its maximal activity.
What two nuclei normally send electrical signals from the hypothalamus to the pituitary?
The Supraoptic, and Paraventricular
What tube transports hormones from the hypothalamus to the pituitary?
The Hypothalami-Hypophyseal portal vessels
What is considered an extension of the hypothalamus?
The Posterior Pituitary
What is the technical name of the stalk that connects the hypothalamus to the pituitary?
Infundibulum
What is a control difference between the posterior pituitary and the anterior pituitary?
The posterior usually sends out hormones directly, whereas the anterior signals for other glands to release the hormones.
Oxytocin, sometimes referred to as the ___ chemical, and is released from ___
cuddle, the posterior pituitary
What is vasopressin?
anti diuretic hormone ADH released from posterior pituitary
Tropic Effect
stimulates changes
Trophic Effect
stimulates growth (differentiation of its target)
What are two general causes of endocrine disorders?
Primary and Secondary Hyper secretion, and hyper responsiveness
Thyroid: T3 and T4, what is more abundant, and what is more active?
T4 more abundant, T3 more active
What turns T4 into T3?
Deiodinase
What are the anatomical components of a thyroid follicle?
The inner colloid and the outer Follicular cells
What does the colloid in a thyroid follicle contain?
proteins, thyroglobulin, enzymes
What do the follicular cells in a thyroid follicle do?
provide stuff for the colloid, and exit for colloid particles
For thyroid hormone synthesis, describe the process of “trapping”
Iodide is cotransported with Na+ into the Follicular cells, then it is assisted by pendrin into the colloid where it builds, and is endocytose back into the follicular cell, then secreted into the blood
Hypothyroidism: Causes
Insufficient dietary iodide, or loss of hormone producing thyroid cells
Hypothyroidism: Thyroid size changes
Less thyroid hormone does not cause negative feedback onto the hypothalamus, so the hypothalamus sends a lot of thyroid stimulating hormone, which has a trophic (growth) effect on the thyroid, causing it to swell and grow [goiter]
Hyperthyroidism: Causes
Thyroid tumors have hormone secreting ability and create a lot of TSH, or the TSH receptors are very sensitive [hyperresponsive]
What nervous system are the Adrenal Glands controlled by?
The sympathetic nervous system.
Which part of the adrenal glands release steroids, and which release catecholamines?
Cortex- steroids, Medulle-catecholamines, mostly epinephrine
How are alpha and beta adrenergic receptors characterized?
By how well they take a message from norepinephrine vs. epinephrine.
What does aldosterone affect?
mineralocorticoid, alters pH and ion concentration
Where is cortisol released from>
The zona fasciculate of the adrenal cortex
What is cortisol known as?
The stress hormone
What are some basal level functions of cortisol?
Blood pressure, metabolic activity, anti inflammatory functions, fetal development
CRH
corticotropin releasing hormone
ACTH
adrenocorticotropic hormone