Lecture 3 Flashcards by Alison Anagnos

What is the difference between a neurotransmitter and a hormone?

Neurotransmitters go from neurons to act locally, while hormones travel throughout the body from glands to their target organs.

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What are some examples of paracrine signaling pathways?

Platlets
Our responses to allergens
Tissue repair
Scar tissue formation
Blood clotting
Ovaries with estrogen

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What are some examples of autocrine signaling pathways?

Il-1
T lymphocytes
Metastasis of cancer

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What are the cytokine peptides?

IL, lymphokines, monokines, IFNs, colony stimulating factors, and chemokines

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What functions of the body do hormones generally cover?

Metabolism
Growth and Development
Water and electrolyte balance
Reproduction
Behavior

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What are the major endocrine glands/tissues of the body?

Hypothalamus
Pineal gland
Pituitary gland
Thyroid gland
Parathyroid gland
Thymus gland
Adrenal glands
Stomach
Pancreas
Kidneys
Adipose tissue
Small Intestine
Ovaries/Testes

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What glands/tissues secrete protein and polypeptide hormones?

Anterior and Posterior pituitary glands
Pancreas
Parathyroid gland

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Where are protein and polypeptide hormones produced in the cell?

Rough ER of endocrine cells. Generally stored or bound to cell membrane until needed.

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What hormones are steroids?

Aldosterone and Cortisol (adrenal cortex)
Estrogen and Progesterone (Ovaries & Placenta)
Testosterone (Testes)

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What are some characteristics of steroids?

Derivatives of cholesterol
Fat soluble
Diffuse easily over cell membranes and then to the blood to go to their targets.
Not stored

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What are the tyrosine derivatives?

T4 & T3
Epinephrine/Norepinephrine

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How are T3 and T4 stored?

Synthesized by the thyroid and then made into a protein called thyroglobulin. Thyroglobulin is stored in large vesicles in the thyroid gland until needed.

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How does the secretion of T3 and T4 occur?

Amines are split off of thyroglobulin, releasing free hormones into the bloodstream.
The hormones combine with plasma proteins ad then are slowly released to their target organ.

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Does the adrenal medulla produce more epinephrine or norepinephrine?

Epinephrine

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How does the adrenal medulla store its hormones?

Epi/Norepi are stored in preformed vesicles until they are secreted.

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What are the neuroendocrine hormones released by the hypothalamus?

Thyrotrophin-releasing hormone (TRH -> TSH & prolactin)
Corticotropin-releasing hormone (CRH -> ACTH)
Growth hormone-releasing factor (GHRH)
Growth hormone-inhibiting factor (GHIH)
Gonadotropin-releasing hormone (GnRH -> LH & FSH)
Dopamine/prolactin-inhibiting factor (PIF)

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What are the hormones secreted by the anterior pituitary gland?

Growth Hormone (somatotropin)
Thyroid stimulating hormone (TSH)
Adrenocorticotropin hormone (ACTH)
Prolactin
Follicle-stimulating hormone (FSH)
Luteinzing hormone (LH)

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Which anterior pituitary hormones cause effects directly?

Prolactin -> breasts
Growth Hormone -> many organs

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What is the effect of growth hormone on blood sugar levels?

Anti-insulin, so it increases blood sugar.

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What stimulates the release of GH?

Starvation (especially protein deficiency)
Hypoglycemia
Low fatty acid concentrations in blood
Exercise
Excitement
Trauma
Ghrelin

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What are the hormones secreted by the posterior pituitary gland?

Antidiuretic hormone (ADH) aka vasopressin
Oxytocin

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What hormones are secreted by the thyroid gland?

T4
T3
Calcitonin (lower blood calcium levels)

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In what part of the cell do thyroid hormones act?

Nucleus. They cause the synthesis of new proteins to carry out a variety of metabolic effects.

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What condition typically is associated with elevated TSH?

Hypothyroidism

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What condition typically is associated with abnormally low TSH?

Hyperthyroidism

What are the symptoms of hyperthyroidism?

Weakness Fatigue Excitability Sweating Weight loss Diarrhea Muscle weakness Nervousness Hand tremors

What are the symptoms of hypothyroidism?

Fatigue Weakness Depression Irritability Weight gain Coarse, dry hair and skin Sensitivity to cold Muscle cramps and aches

Which thyroid disorder is more common, hyper or hypothyroidism?

Hypothyroidism.

What hormones does the adrenal cortex secrete?

Aldosterone Cortisol Androgens

What are the layers of the Adrenal Cortex (Superficial to deep)

Zona Glomerulosa (15%) Zona Fasciculata Zona Reticularis

What layer of the adrenal cortex is aldosterone made in?

Zona Glomerulosa

What stimulates the secretion of aldosterone?

Angiotensin II Potassium

Where are cortisol and androgens made in the adrenal cortex?

Zona Fasciculata Zona Reticularis

What is the function of PTH?

Increases blood calcium, releasing it from bones and absorbing it from food.

Which hormones typically have long onsets and durations of action?

Thyroxine Growth hormone

How big are hormone concentrations?

Incredibly tiny! One millionth of one millionth of a gram (picogram) per mL of blood. A few millionths of a gram per mL

What is an example of a positive feedback loop for hormones?

Secretion of estrogen causes a surge in LH. LH then goes to the ovaries, causing more estrogen to be secreted. More estrogen then leads to more LH until ovulation is complete.

Why does the body use negative feedback loops for hormones?

It helps ensure a proper level of hormone activity at the target tissue. The hormone/its products will prevent oversecretion/overactivity at the target tissue.

What are some cyclical variations of hormone release?

Seasonal changes Various stages of development and aging Diurnal cycles Sleep

How is growth hormone affected by sleep?

Most of our GH is secreted in the beginning half of our sleep, getting reduced in the 2nd half of sleeping.

Which type of hormones are water-soluble?

Peptides and catecholamines, which dissolve in plasma.

How do steroids and thyroid hormones travel in the blood?

They stay bound to plasma proteins until they dissociate, so they are reservoirs.

What is the clearance rate of a hormone?

It is the rate at which it is removed from the body.

What two properties determine a hormone's concentration in the blood?

Rate of hormone secretion into blood Clearance rate

In what ways can hormones be cleared from the bloodstream?

Metabolism by tissues Binding with tissues Excretion by liver into bile Excretion by kidneys into urine

Insulin is a hormone of _________

Abundance

What is the significance of a C-peptide?

C chains are always secreted in the same amount of human-made insulin. We can measure how much C-peptide has to see how much natural insulin they are producing.

What factors can increase insulin secretion?

Elevated blood glucose Elevated free fatty acids and amino acids (FFA, AA) GI Hormones such as gastrin & secretin Parasympathetic stimulation Insulin resistance/obesity Sulfonylurea drugs (Victoza)

What factors decrease insulin secretion?

Decreased blood glucose Fasting Leptin Exercise

What are the effects of insulin?

Promotes uptake of glucose by many cells, and in this way controls carb metabolism

What are the effects of glucagon?

increases synthesis and release of glucose from the liver into the body fluids

What are the effects of ADH?

Increases water reabsorption by the kidneys and causes vasoconstriction, raising blood pressure. Peptide

What are the effects of T4 and T3?

T4: thyroxine T3: triiodothyronine Increases the rates of chemical reactions in most cells, increasing body metabolic rate Amine

What are the effects of calcintonin?

Promotes deposition of calcium in the bones and decreases extracellular fluid calcium ion concentration Peptide

What are the effects of TSH?

Stimulates synthesis and secretion of thyroid hormones (T4 and T3) Peptide

What are the effects of ACTH?

Stimulates synthesis and secretion of adrenocortical hormones (aldosterone, cortisol, and androgens) Peptide

What is the main difference between the anterior and posterior pituitary gland?

The hypothalamus sends its hormones to the anterior pituitary via the hypothalamic-hypophyseal portal vessels. The anterior then secretes its hormones into the capillary bed surrounding it. The posterior pituitary is considered an extension of the hypothalamus, so it simply sends its signals via the hypothalamic-hypophyseal tract, where it releases vesicles at the end of the axons.

What is the effect of aldosterone?

Increases sodium reabsorption by the kidneys Increases potassium excretion by the kidneys Increases hydrogen ion excretion by the kidneys. Steroid

What happens if an infant is deficient in T3 and T4?

Neurological impairments. Thyroid hormones are essential in the development of synapses and neurons.

What is the effect of cortisol?

Controls metabolism of proteins, fats, and carbohydrates. Has anti-inflammatory effects. Steroid

What are the two drugs mentioned that release GLP-1 agonists?

Victoza and Ozempic

Lecture 3 Flashcards

(61 cards)