BIO 142 Chapter 16: Endocrine System

4 steps of hormone secretion

1. Hormones secreted in interstitial fluid, then enter blood 2. Diffusing through/between cells of tiny blood vessels (capillaries) which are located in networks (capillary beds). When blood exits capillaries, it transports hormones to heart through larger blood vessels (veins) 3. After leaving the heart, blood transports hormones to rest of body through arteries, which branch out repeatedly into smaller vessels and finally capillary beds 4. Once in capillaries, hormones diffuse out of blood into interstitial fluid to reach receptors on target cells

Autocrine secretion

A chemical secreted by cells into ECF that elicits effects from the same cell

Anterior pituitary hormone that stimulates release of hormones from adrenal cortex

ACTH

Hormones that work synergistically to retain water:

ADH and aldosterone

Paracrine signals:

Act on neighboring cells

Lepton is a hormone produced by ___

Adipose Tissue

Which gland secretes mineralocorticoids?

Adrenal cortex

Hormone that regulates blood sodium concentration, by stimulating sodium conservation in kidneys:

Aldosterone (also for Blood Pressure balance)

Hypersecretion of ___ is likely to lead to high BP and hypernatremia (excess blood sodium ion concentration)?

Aldosterone.

Effect from secretions of adrenal cortex:

An increase in blood pressure and heart rate

Thyroxine (T4) functions in:

An increase in general rate of metabolism

Low levels of T3 and T4 will cause?

An increase of TSH secretion from anterior pituitary gland via negative feedback

Growth hormone (GH) does not stimulate:

An increased rate of glycogen formation

___ are hormones that act on same target cells but have opposite effects

Antagonists

Primary organs of endocrine system

Anterior pituitary gland, thyroid gland, parathyroid glands (posterior thyroid gland), paired adrenal cortices (superior surface of kidneys), endocrine pancreas, thymus, ovaries/testes. Ductless glandular epithelial cells.

All of the following tropic hormones are released by anterior pituitary gland, except:

Antidiuretic hormone (ADH)

___ signals consist of chemicals secreted by cells into ECF that elicit effects from the same cell

Autocrine

Posterior lobe of pituitary gland is not a true endocrine gland - why?

Because it is only a hormone storage area that receives hormones from hypothalamus for release

___ cells of pancreas produce insulin

Beta cells

___ are major targets of GH

Bone and skeletal muscle

Hormones produced by parafollicular cells in thyroid

Calcitonin

Hormone released by kidneys that stimulates absorption of calcium ions from digestive tract

Calcitriol

Unlike nervous system, the effects of hormones ___?

Can require seconds, hours, or even days for their effects

What is the name of the hormone producing cells of the adrenal medulla?

Chromaffin cells

Which hormone acts as a potent anti-inflammatory agent?

Cortisol

Which hormones play key roles in long-term response to stress?

Cortisol, growth hormone, and glucagon

Secretion of insulin in pancreas results in:

Drop in blood sugar levels

Compare transport of hydrophobic and hydrophilic hormones in blood from site of release to target cells.

Hydrophobic: Bound hormones (form complexes with binding proteins in plasma) and don't associate with water molecules in plasma. Protein-binding allow hydrophobic hormones to transport safely through blood. Hydrophilic: Free hormones (generally small, amino-acid based hormones) and able to freely associate with water, travel freely through water-based plasma of blood. Hydrophilic cannot cross phospholipid bilayer of plasma membrane to enter target cells because repelled by fatty acid tails of phospholipid bilayer. Hydrophobic cant cross membranes because of attraction between hormones and fatty acid tails. Thyroid hormone = exception, needs transport protein

What stimulates release of PTH?

Hypocalcemia (low calcium levels in blood)

All the following structures are primary organs of endocrine system except:

Hypothalamus

The ___ is the link between the nervous and endocrine systems

Hypothalamus

Neuroendocrine glands

Hypothalamus and pineal gland (in brain), adrenal medulla in core of adrenal gland. They consist of nervous tissue but secrete chemicals that act like hormones called neurohormones.

Hypothalamus and pituitary gland are related because

Hypothalamus secretes releasing and inhibiting hormones that influence the pituitary gland

Aldosterone functions to:

Increase sodium reabsorption

Aldosterone secretion is NOT stimulated by:

Increased plasma volume

Which is not an effect of epinephrine?

Increased water retention

What hormone is the primary antagonist of glucagon?

Insulin

What element is necessary for the production of triiodothyronine (T3) and thyroxine (T4)? magnesium potassium calcium iodine

Iodine

___ is required for thyroid hormone synthesis

Iodine

Renin is produced by ___

Kidneys

What cells respond to glucagon and break down glycogen and release glucose?

Liver cells

What cells respond to insulin?

Liver cells and most other cells in body

Which hormone causes testes to produce testosterone?

Luteinizing hormone (LH)

Compare actions of nervous system and endocrine system - similarities

Maintain homeostasis of nearly all physiological variables. Cells of both use chemicals to communicate with other cells.

Hormones produces by zona glomerulusa:

Mineralocorticoids

What is the major function of the endocrine system?

Endocrine system releases hormones into bloodstream to reach receptors on target cells

Which hormone is NOT secreted by adrenal cortex?

Epinephrine

Which of the following is not steroid-based?

Epinephrine

Response to stress, blood concentration of:

Epinephrine and cortisol increased

Hormone released by kidney that stimulates RBC synthesis:

Erythropoietin

This hormone is NOT matched correctly:

Erythropoietin increases white blood cell formation (it increases RBC formation, not white)

Which hormone stimulates development of female secondary characteristics (adipose deposition in breast)?

Estrogen

The following is false:

Exercise will decrease glucagon secretion

Aldosterone regulates:

Extracellular sodium and potassium ion levels

Aldosterone regulates___?

Extracellular sodium and potassium ion levels

___ exerts its effects mainly on reproductive organs

Follicle-stimulating hormone (FSH)

Somatotrophs are stimulated by:

GHRH

What type of tissue makes up the adenohypophysis or anterior pituitary gland

Glandular epithelium

Alpha cells of pancreas produce:

Glucagon

Hormone produced by alpha cells of pancreas

Glucagon

Which hormones are released in response to decreases in blood glucose concentration?

Glucagon

The ___ is responsible for producing atrial natriuretic peptide (ANP)?

Heart

secondary endocrine organs/tissues

Heart, kidneys, small intestine, adipose tissue, and sometimes testes/ovaries

What will cause Negative Feedback inhibition of HPA axis?

High cortisol levels

Which type of stimulation regulates secretion of GH from anterior pituitary gland?

Hormonal stimulation

Chemical messengers released by endocrine glands to regulate some functions of other cells are known as __________. antibodies hormones neurotransmitters electrolytes

Hormones

The endocrine system secretes ___ into blood to be transported by target cells

Hormones

Endocrine glands secrete ___ into bloodstream, where they travel to specific sites called ___.

Hormones; target tissues

Insulin operates under ___ stimulation.

Humoral stimulation

What type of hormones can cross plasma membrane to bind to a receptor in cytosol or nucleus?

Hydrophobic hormones

Most hormone secretion is regulated as a part of:

Negative feedback loop

Region of adrenal gland that produces mineralocorticoids:

Zone Glomerulus

Avery has high blood pressure and hypernatremia (excess blood sodium ion concentration). The hypersecretion of which hormone could lead to his condition? aldosterone insulin calcitonin glucagon

aldosterone

A second messenger for hormone response is:

cAMP

What hormone is made by the parafollicular cells of the thyroid gland? thyroxine (T4) calcitonin triiodothyronine (T3) parathyroid hormone (PTH)

calcitonin

paracrine secretions

chemical secreted by cells into ECF to influence nearby target cells

The secretion of parathyroid hormone is controlled primarily by the

concentration of serum calcium

What is the function of ventral hypothalamic neurons?

control secretion of thyroid stimulating hormone (TSH)

Aldosterone regulates __________. blood glucose levels extracellular sodium and potassium ion levels blood calcium ion levels blood iodide ion levels

extracellular sodium and potassium ion levels

Nina is researching hormones that can stimulate and inhibit the release of growth hormone from the anterior pituitary. Predict the type of stimulation that regulates the secretion of growth hormone. humoral stimulation cellular stimulation neural stimulation hormonal stimulation

hormonal stimulation

What type of hormone can cross the plasma membrane to bind to a receptor in the cytosol or nucleus? protein hormones amine hormones hydrophobic hormones hydrophilic hormones

hydrophobic hormones

What is NOT an effect of parathyroid hormone (PTH)? increased absorption of calcium ions by the small intestine increased release of calcium ions from bone increased osteoblast activity increased reabsorption of calcium ions from fluid in the kidneys

increased osteoblast activity

What stimulates the release of ADH, or vasopressin?

increasing solute concentration of the blood

Which hormone lowers blood glucose levels? insulin glucagon growth hormone cortisol

insulin

hormone produced by pineal gland

melatonin

What is NOT a primary target tissue of cortisol? nervous tissue muscle tissue adipose tissue liver tissue

nervous tissue

Harrie has recurring kidney stones. Which hormone should be checked for normal levels? calcitonin parathyroid hormone (PTH) triiodothyronine (T3) thyroxine (T4)

parathyroid hormone (PTH)

What is delivered over the hypothalamic-hypophyseal portal system? releasing and inhibiting hormones stimulating hormones trophic hormones tropic hormones

releasing and inhibiting hormones

What does thyroid-stimulating hormone (TSH) target? hypothalamus anterior pituitary (adenohypophysis) posterior pituitary (neurohypophysis) thyroid gland

thyroid gland

What is the primary effect of antidiuretic hormone (ADH, or vasopressin)? water retention by the kidneys increases urine production by the kidneys blood glucose regulation sodium retention by the kidneys

water retention by the kidneys

Compare actions of nervous system and endocrine system - differ

Nervous system operates through a series of neurons that directly affect target cells through release of neurotransmitters, effects are almost immediate but short-lasting. Endocrine cells don't come into close contact with target cells, different mechanism of action (hormone secretion) and hormones can take seconds to several hours to days to elicit effects, generally longer lasting

Tissue type of posterior pituitary:

Nervous tissue

The cells of the nervous system communicate by ___ whereas cells of the endocrine system communicate via ___

Neurotransmitters; hormones

Which hormone causes contraction of uterus during birth?

Oxytocin

Cells that secrete glucagon are located in?

Pancreas

Which gland has an endocrine and exocrine function:

Pancreas

When blood glucose levels increase

Pancreas releases insulin

Hormone secreted by chief cells of parathyroid glands

Parathyroid hormone (PTH)

Melatonin is secreted by ___ to regulate sleep/wake cycle.

Pineal gland

With which gland does the hypothalamus have a close anatomical and physiological relationship?

Pituitary Gland

With which gland does the hypothalamus have a close anatomical and physiological relationship? adrenal gland pituitary gland pineal gland thyroid gland

Pituitary gland

Releasing hormones from hypothalamus are carrier to the anterior pituitary gland by ___?

Portal veins

Steroid hormones

Produced by adrenal cortices, testes and ovaries. All are hydrophobic, lipid-soluble because they can mix with fats and are stored in adipose tissue. The steroid hormones are the estrogens (female sex steroids), androgens (male sex steroids), progestins, mineralocorticoids, glucocorticoids, and vitamin D.

Amino acid based hormones

Produced by anterior pituitary gland, pancreas, thymus, thyroid, and parathyroid. Consist of 1+ amino acids Most are hydrophobic (interact with water molecules) except thyroid hormone Examples of amino acid-derived hormones include epinephrine and norepinephrine, which are synthesized in the medulla of the adrenal glands, and thyroxine, which is produced by the thyroid gland. The pineal gland in the brain makes and secretes melatonin which regulates sleep cycles.

General functions of endocrine system

Regulatory system, synthesizing and secreting chemical messengers (hormones) into blood

What is delivered over hypothalamic-hypophyseal portal system?

Releasing and inhibiting hormones

Hyperthyroidism

Results in a decrease in TSH

Hypothyroidism

Results in an increase of TSH

Aldosterone promotes homeostasis of ion concentrations by causing kidneys to:

Retain sodium and excrete potassium

Which hormone would not be water soluble?

Steroids

Cortisol acts to:

Stimulate gluconeogenesis

What is NOT an effect of cortisol:

Stimulate inflammatory response

Which of following is not short-term effect of GH?

Stimulates storage of glucose in muscle

Thymosin and thymopoietin assist in maturation of:

T lymphocytes

What is an example of an anterior pituitary hormone?

TSH

Liver cells respond to insulin by?

Taking in glucose and converting it to glycogen

Parathyroid glands maintain adequate levels of blood calcium by:

Targeting bone and activating osteoclasts to release calcium

Hyperthyroidism is most likely to result in:

Tendency toward weight loss

Testosterone is produces by ___?

Testes

Organs which are both primary and secondary endocrine organs

Testes and ovaries

When blood glucose levels are low...

The pancreas releases glucagon, which eventually causes blood glucose levels to increase.

What does TSH target?

Thyroid gland

Which structure is a primary endocrine gland?

Thyroid gland

Thermoregulation is a function of?

Thyroid hormones

What hormones determine basal metabolic rate at rest when fasting?

Thyroid hormones

___ is caused by destruction of insulin-producing beta cells of pancreas by immune system.

Type I diabetes mellitus