2025 Physiology Exam 4 Flashcards
Lectures 17-22: Endocrine, Metabolism, Neurophysiology
Endocrinology
Hormones Are Defined By Their Mode of Action
KNOW:
Hormone
Where it comes from
What triggers its synthesis and/or release
Hormone Transportation
Water = another name polypeptide
Thyroid = actually proteins, but act like steroids
Three Hormone Classes
All steroids have a backbone of cholesterol
Hormone Transportation
KNOW the Transcription and Translation overview
Protein and Peptide Hormones
TRH from hypothalamus goes to anterior pituitary to release TSH
TSH goes to Thyroid and tells it to stimulate/release TH
ADH and Oxytocin come from hypothalamus and stores in posterior pituitary for eventual release (CONFIRM ALL THIS!!!)
Insulin and Glucagon are antagonist to each other
Synthesis of Steroid Hormones
Cholesterol is the backbone of all steroid hormones
Steroid Hormones
Very little storage = made de novo
Synthesis of Tyrosine-Derived Hormones
Colloid - T3 and T4 are made here
Space between the follicles is called the medulla and have C-Cells, which produces calcitonin (antagonist to PTH)
Tyrosine (Amine) Hormones
Thyroid hormones contain Iodine
Are poly peptides… but lipid soluble and travel in blood by thyroxine binding globulin
Hormone Concentration Is a Balance Between Secretion and Clearance
Summary of Clearance Determinants
Only Free Hormones are active
Hormones bound to a carrier mechanism are not active
Plasma [Hormone] Is Very Low
What kind of hormone attaches to what ones?
Lipophilic to look for receptor inside
KNOW
Control of Hormone Secretion
KNOW HOW THIS WORKS AGAIN
Most common is Negative Feedback… as hormone does its job it works to terminate itself
KNOW NEGATIVE and POSITIVE
Negative Feedback
Example of Negative Feedback
Positive Feedback
Example of Positive Feedback
Insulin is another example
Pituitary Anatomy
Sits in the Sella turcica of sphenoid bone
Major Hormones of the
Anterior Pituitary
Growth hormone
Adrenocorticotropin
(ACTH, corticotropin)
Thyroid-stimulating hormone
(thyrotropin)
Prolactin
Gonadotropins
(FSH and luteinizing)
Melano hormone or something like this?
Sites of Action for
Pituitary Hormones
Gland that produces Hormone
Target of hormone
What regulates hormone release
Cell Type and Hormone
Hypothalamic Control of the Anterior Pituitary
Hypothalamic-Hypophysial Portal System
Portal system = capillaries between two veins
How does this work?
Posterior Pituitary does not use portal system
What does it use again???
Hypothalamic-Hypophysial Regulatory Hormones (Hypophysiotropic)
Know somatostatin
Hypothalamic-Hypophysial Control Summary
Anterior Pituitary Hormones
Growth Hormone… controlled by the hypothalamus hormones:
GHRH
Somatosonin
Growth Hormone (Somatotropin)
Metabolic Actions of Growth Hormone
Increase Protein Synthesis
Increase Fat Utilization
Decrease Carbohydrate Utilization
Growth Hormone Increases Protein Synthesis
Growth Hormone Increases Fatty Acid Metabolism
Use Fat for energy
GH antagonist to Insulin
Growth Hormone Inhibits Utilization of Carbohydrate
↓ Glucose uptake in muscle
↓ Glucose uptake in fat
↑ Gluconeogenesis
(Hepatic production)
Blood level glucose increases
Diabetogenic Effects of Growth Hormone
Because decrease of Glucose in the muscles, leads to more glucose in the blood
Growth Hormone-Bone Growth
Acromegaly
Local tumor effects
↑ Pituitary, visual field defects, headache
Somatic systems
Acral enlargement, prognathism, carpal tunnel syndrome
CV system
Ventricular hypertrophy, cardiomyopathy, Hypertension, heart failure
Pulmonary system
Sleep disturbances, sleep apnea
Visceromegaly
Tongue, thyroid gland, liver, spleen, liver, kidney, prostate
Metabolic
Insulin resistance, fasting hyperglycemia,
Posterior Pituitary (Neurohypophysis)
Hypothalamic Control of Growth Hormone
Antidiuretic Hormone (Vasopressin)
ADH or AVP
Stimulus:
High serum osmolarity
Hypotension
ADH works on the collecting duct
Renal Tubular Actions of ADH
ADH works on the collecting duct
Control of Antidiuretic Hormone
Lower serum osmolarity
Increase fluid in system
Oxytocin
Thyroid Hormones
acts like a steroid, there fore lipid soluble
Major Hormones of the Thyroid Gland
Dietary Iodide Is Necessary for Thyroid Hormone Production
Thyroid Hormone Production-Step 1
Iodine trapped by colloid, then goes back into cell
Look up more???
** He breezed over the next steps…
Metabolic Actions of Thyroid Hormones
Cardiovascular Effects of Thyroid Hormone
Other Physiological Affects of
T3 and T4
Increase Rate of Bone Growth
Early cessation of growth
Affects children
Control of Thyroid Hormones
KNOW this a little more
Adrenal Anatomy
Adrenal Cortical Hormones (1 of 2)
Mineralocorticoids = aldosterone is the big one
Glucocorticoids = cortisol is the big one
Androgenic
Adrenal Medullary Hormones—Amine
Adrenal Steroid Clearance
Glucocorticoid and Mineralocorticoid Activity
Aldosterone
Lipid Soluble
Aldosterone (60%)
Corticosteroid binding globulin (CBG)
Plasma proteins (albumin, prealbumin)
Aldosterone Action in the Kidneys
Physiological Actions of Aldosterone
Aldosterone has an inverse relationship with potassium
Aldosterone Control
YOUTUBE THIS POTASSIUM and ALDOSTERONE RELATIONSHIP…
Summary of Aldosterone Control
During a Chronic Infusion of Aldosterone …
KNOW HOW TO ANSWER THESE QUESTIONS
Cortisol
Glucocorticoids
Cortisol (95%)
90% circulating bound to cortisol binding globulin, plasma proteins (albumin, prealbumin)
Because it is so active
Corticosterone (4%)
Cortisol—Carbohydrate Metabolism
Cortisol—Protein Metabolism
Cortisol—Fat Metabolism
Cortisol
Anti-inflammatory properties
Hypothalamic Control of Cortisol
Hormonal Control of Calcium
Vitamin D
Parathyroid hormone (PTH)
Calcitonin (produced by the C-Cells in Thyroid)
Calcium has an inverse relationship with Phosphate???
Vitamin D
Starts in skin, kidney is the last step**
Helps with absorption of calcium (and phsosphate) in intestines**
Promotes intestinal absorption of calcium
Promotes intestinal absorption of phosphate
Increases renal reabsorption of calcium and phosphate (minor)
Enhances bone calcification (by increasing calcium transport, activating osteoblasts?)
Parathyroid Hormone (PTH)
Parathyroid Anatomy and Function
Major Actions of Parathyroid Hormone
1,25 dihydroxycholecalciferol = vitamin D
Osteolysis = breakdown of bone = activation of osteoclasts
PTH Effect on Bone
Control of PTH by Calcium (ECF)
Calcitonin
Opposes effect of PTH (i.e., it decreases plasma calcium)
Produced in the thyroid gland (parafollicular cells… within medulla of thyroid, also called C-Cells)
Stimulated by increased plasma calcium (hypercalcemia)
Decreases osteoclast activity and osteolysis
Decreases osteoclast formation (and subsequent osteoblast)
Only a transient (hours) effect on plasma calcium
Summary of Calcium Control
Pancreas Anatomy and Major Hormones
Islets of Langerhans
Alpha cells (25%) – Glucagon
Beta cells (60%) – insulin, amylin
Delta cells (10%) – Somatostatin
PP cells (5%) – Pancreatic polypeptide
Pancreas Anatomy—Cell Types
Insulin
Insulin Increases the Cellular Uptake of Glucose
Cellular Action of Insulin
Brain and active muscles are independent of insulin???
Insulin Promotes Glucose Storage in the Liver
Liver Is a Source of Glucose in the
Postabsorptive State*
Effect of Insulin on Protein
Insulin Is Regulated by Glucose
Regulation of Insulin
Glucagon
Antagonistic to Insulin
Increase Blood Sugar… goes to Liver and tells it to breakdown the stored glucose (glycogen) to release into the blood
Glucagon (Actions Oppose Insulin)
Glycogenolysis = glycogen into glucose
Gluconeogenesis = protein breakdown for energy
Somatostatin
Increased by:
Glucose
Amino acids
Fatty acids
GI hormones
Purpose:
Maximize use of “fuel”
Growth hormone inhibition
Actions:
Paracrine action to inhibit insulin and glucagon secretion
Decreases stomach, duodenum, gall bladder motility
Decreases secretion and absorption in GI tract
Epinephrine
Metabolic Effects of Epinephrine
Summary of Glucose Regulation
Liver—stores/releases glucose
Insulin—increased by glucose, returns glucose to normal (80–90 mg/dL fasted)
Glucagon—increased by low glucose, returns glucose to normal
Hypoglycemia—stimulates sympathetic nerve increase in epinephrine to increase glucose from the liver
Hypoglycemia—increases growth hormone/cortisol, promotes fat utilization, decreased glucose utilization
Importance of Glucose Regulation
Brain, retina, gonadal epithelium—only use glucose
Too much increases extracellular osmotic pressure
(cellular dehydration)
Too much causes urinary loss of glucose
Urinary loss of glucose-osmotic diuresis
Too much causes vascular damage
The Female Sexual (Menstrual) Cycle
KNOW THIS!!!
Follicular Phase—Ovulation
High estrogen leads to high LH leads to ovulation… after which you see progesterone
Endometrial Cycle and Menstruation
Physiological Effects of Estrogen
Male Reproductive….
Look at PowerPoint, short…
