VPHY 3100 UGA Test 2

Endocrinology

The study of endocrine glands/tissue, the hormones they release, and their effects on target tissues

Hormones

Are carried via the blood; regulate body metabolism, growth, and reproduction

Complementary or antagonistic

Target tissues are regulated by multiple hormones and downstream effects may be _______ or _______.

Physiological Range

"Sensitization" or "upregulation"

Pharmacological ranges

"Desensitization" or "downregulation"

Adrenal Medulla

(Amino Acid Derivatives) Epinephrine and Norepi are secreted by...

Pineal gland

Amino acid derivative; melatonin is derived from the...

Peptides and proteins

Hypothalamic & pituitary hormones; insulin and glucagon (pancreas); parathyroid hormone

Adrenal cortex

Corticosteroids are produced by the...

Gonads

Sex steroids are produced by the...

Hydrophilic hormones

_____ ______ interact with cell surface receptors at target tissues (all peptide &protein hormones; epi and Norepi)

Hydrophobic (or lipophilic) hormones

_____ _____ interact with intracellular receptors at target tissues (steroid or thyroid hormones)

Enzyme linked (RTKs)

_____ receptors act through intracellular 2nd messengers (cAMP, Ca2+, kinases)-insulin, growth factors

GPCRs

Act through intracellular 2nd messengers (cAMP, Ca2+, kinases)-epinephrine, norepi

Intracellular Receptors

Act as a transcription factor in the nucleus; steroids, thyroid hormones

Islets of Langerhans

_______ comprise the endocrine portion of the pancreas

Glucagon

Alpha cells secrete...

Insulin

Beta cells secrete...

Anabolism; catabolism

(Cellular metabolism) insulin-->_____

Glucagon -->___

Liver, skeletal muscles, adipocytes

Pancreatic hormone's target tissues: (3)

Anabolism

Uses amino acids, sugars, fatty acids etc to create proteins, polysaccharides , lipids, and nucleic acids

Catabolism

Uses energy containing nutrients like carbs, fats, and proteins that result in energy depleted CO2 H2O and NH3

Receptor Tyrosine Kinases (RTKs)

____ are the most prevalent type of enzyme-linked cell surface receptor; the insulin receptor for example

Kinases

Enzymes that phosphorylate proteins

Tyrosine kinases

Attach phosphate groups to tyrosine residues within proteins

Glucose uptake and anabolic reactions

The result of insulin receptor activation is...

Glycogen synthesis and fat storage

High levels of glucose results in increased production of insulin which increases...

Hepatocytes

Move glucose into liver cells when [glc]blood is high and out when [glc]blood is low

Skeletal muscle, cardiac muscle and adipose tissue

Insulin-responsive GLUT4 recruitment occurs only in...

[insulin]blood

When ____ increases, 95% of blood glucose is taken up by muscle and fat tissues

Decrease gluconeogenesis and increase glycogen synthesis

Major effect of insulin at the liver

Increase glycogenolysis and gluconeogenesis

Major effect of glucagon at the liver

[glucagon]blood; [insulin]blood

Exercise increases ____ and decreases ____

Anterior lobe

This part of the pituitary gland is involved in hormonal regulation by the hypothalamus

Posterior lobe

Part of the pituitary gland that is the neural extension of the hypothalamus

ADH and Oxytocin

The hypothalamus produces _____ and they are secreted by the posterior pituitary gland

Hypothalamo-hypophyseal tract

Supraoptic & paraventrical nuclei of the hypothalamus produce oxytocin and ADH which are transported down the...

Hypothalamo-hypophyseal portal system

Hypothalamic nerve endings secrete releasing and inhibiting hormones into a capillary/venue system known as...

Growth Hormone (GH)

Somatotropin; promotes tissue growth

Thyroid-stimulating hormone (TSH)

Promotes production of t3 and t4 in the thyroid

Adrenocorticotropic hormone (ACTH)

Promotes secretion of glucocorticoids in the adrenal cortex

Follicle-stimulating hormone (FSH) and Luteinizing hormone (LH)

The gonadotropic hormones; promotes gamete production & sex steroid secretion in the gonads

Prolactin (PRL)

Stimulates milk production in the mammary glands

Adrenal Medulla

What is stimulated by the sympathetic nervous system?

Adrenal Cortex

Has three zones: Zona glomerulosa (mineral corticoids), Zona fasciculata & Zona reticularis (glucocorticoids and sex steroids)

Increase

The sympathoadrenal effects of the Catecholamine hormones are generally an ________ in cardiac output and glycogenolysis and lipolysis etc

Intracellular secondary messengers (cAMP and Calcium)

Epinephrine released from the Adrenal Medulla mediates its effects at target tissues via activation of GPCR's that increase...

Beta adrenergic

cAMP works through what kind of receptors?

Alpha adrenergic

Ca2+ works through what kind of receptors?

Regulation of Na+ and K+

Mineralcorticoids are responsible for...

Aldesterone

Type of Mineralcorticoid that increases blood volume and pressure; balances electrolytes

Regulation of glucose and other metabolites

Glucocorticoids are responsible for...

Cortisol

Increases blood glucose levels by stimulating gluconeogenesis and inhibiting glucose utilization in the tissues; it also increases free fatty acid levels in the blood by stimulating lipolysis. Role in immune suppression and inhibition of inflammation

Sex Steroids

weak androgens that supplement gonadal hormones

Steroid Hormones

Synthesized from cholesterol and produced in the adrenal cortex; have hydrophobic fused-ring structures

Carrier Proteins

Steroid Hormones travel through the blood by binding to...

Intracellular nuclear hormone receptors

Steroid hormones bind to and activate _____ which then function as transcription factors

Negative Feedback

Hypothalamic-pituitary-adrenal axis shows that in times of stress, ________ occurs to cause a rise in Cortisol

T3 and T4

Secreted by the follicular cells of the Thyroid gland; regulates the body's metabolism, growth, and development; stimulated by TSH release from Anterior pituitary

Calcitonin

Secreted by parafollicular cells of the Thyroid gland; regulation of blood calcium levels

Hypothalamus, Anterior Pituitary gland, thyroid gland

_______ secretes TRH

_______ secretes TSH

_______ secretes T3 and T4

Thyroid follicular cells

Transports iodide from the blood into the colloid; Iodine is attached to tyrosine residues on thyroglobulin

T3 and T4

derivatives of tyrosine, hydrophobic, and its target tissues are the liver (glucose metabolism and gluconeogenesis) and skeletal muscle cells (promotes normal growth and development)

TBG (Thyroxine-binding globulin)

carrier protein for t4 in blood

Trophic effect, hormonal effect

A _____ will produce a growth of the thyroid while a _____ will produce t4 after TSH stimulation

Hypothyroid; hyperthyroid

decreased levels of t4 in blood; increased levels of t4 in blood

Iodine insufficiency

Endemic goiter is a result of ______. Low levels of circulating t4, no negative feedback, elevated TSH, trophic effect on thyroid gland-> goiter

Graves' disease

Toxic goiter is a result of ______. Hyperthyroid condition, autoantibodies mimic TSH effects at thyroid, excessive t4 in blood but autoantibodies circumvent normal negative feedback loop -> goiter

Actin and Myosin; calcium

All muscle contractions occur by sliding of thin and thick filaments called _____ and rely upon increases in intracellular ____.

Sarcomere

smallest contractable unit; striated in appearance; controlled by the somatic motor neurons

Pacemaker cells

automatic rhythmic action potentials and contractions; autonomic motor neurons

Smooth Muscle

no sarcomeres; no striated appearance; controlled by autonomic neurons

Muscle

bundle of fasciculi

fasciculus

bundle of muscle fibers

muscle fiber (myofiber)

muscle cell

myofibril

serially repeating sarcomeres

sarcolemma

plasma membrane of a muscle cell

sarcoplasm

cytoplasm of a muscle cell

sarcoplasmic reticulum

specialized endoplasmic reticulum of a muscle cell

Motor unit

comprised of a single motor neuron and all of the muscle fibers it innervates

Neuromuscular Junction

specialized synapse between the somatic motor neuron's nerve terminal and the motor end plate of the skeletal muscle cell

Excitation/Contraction coupling (E/C)

Transformation of electrical signal in muscle cell into tightening of sarcomeres is called...

T-tubules

Organization of the sarcolemma: _____ invaginate the myofibrils, are continuous with the sarcolemma

Sarcoplasmic Reticulum

Terminal cisternae are closely apposed to the T-tubules; The ____ surrounds myofibrils as a network of interconnected sarcotubules

DHPRs (dihydropyridine receptors)

Transverse tubule voltage gated calcium channel

RyRs (Ryanodine receptors)

Sarcoplasmic reticulum calcium release channel

Shorten

Sarcomeres ______ during muscle contraction without a change in length of their filaments

Z discs; A bands

shortening of myofibrils means movement of _____ closer to one another but the _____ maintain their length

Ca2+

Myosin heads will bind to actin only in the presence of _____

Power Stroke

The ______ causes the sliding of thin filaments across thick filaments

Autonomic and Somatic systems

The Peripheral Nervous system is made up of the ________.

Sympathetic and Parasympathetic systems

The autonomic system is made up of these two systems (arousing and calming)

CNS

brain and spinal cord

PNS

nerves and ganglia outside CNS

12; 31

How many pairs of cranial nerves are there?

How many pairs of spinal nerves are there?

Sensory and Motor fibers

Most nerves are "mixed" meaning that they are comprised of ______.

Autonomic

Central control: hypothalamus, brain stem, and spinal cord; regulation of cardiac muscle, smooth muscle and glands

Somatic

Central Control: frontal cortex and subcortical structures

Autonomic

has two neurons from CNS to effectors and has an excitatory or inhibitory nerve impulse on muscle

Somatic

has one neuron to effector and is excitatory only