Endocrine System

Question 1

Endocrine gland

Answer 1

ductless organ that secretes hormones

Question 2

hormone

Answer 2

chemical messages that travel through the blood to regulate target cells

Question 3

target cell

Answer 3

have specific receptors to which the hormone binds, receptors may be intracellular or located on the plasma membrane

Question 4

what changes can target cells trigger after hormone binding?

Answer 4

• alter plasma membrane permeability
• synthesis of proteins
• activate or inactivate enzymes
• stimulate cell division (mitosis)

Question 5

Hypothalamus

Answer 5

secretes releasing hormones that control the activity of the anterior pituitary gland

Question 6

Pituitary gland (hypophysis)

Answer 6

contains 2 functional lobes-anterior pituitary made of glandular tissue and the posterior pituitary made of nervous tissue

Question 7

Posterior pituitary gland

Answer 7

made of nervous tissue, connected to hypothalamus by neural tissue

• Nuclei of the hypothalamus synthesize hormones that are transported to the posterior pituitary where they are stored and released
• Oxytocin-causes uterine contractions during childbirth and milk ejection reflex during nursing
• Antidiuretic hormone (ADH)-stimulates reabsorbtion of water in the kidneys leading to reduced urine volume

Question 8

Anterior pituitary gland

Answer 8

made of glandular tissue, connected to hypothalamus by the hypophyseal portal system-capillary beds
*produces tropic hormones to stimulate growth of another gland and regulate the release of hormones from other endocrine glands

Question 9

Thyroid stimulating hormone (TSH)

Answer 9

targets thyroid gland to produce hormones

*release stimulated by the hormone TRH from the hypothalamus

Question 10

Adrenocorticotropic hormone (ACTH)

Answer 10

stimulates the adrenal cortex to release glucocorticoids

*release stimulated by CRH from the hypothalamus

Question 11

Follicle stimulating hormone (FSH)

Answer 11

In females-stimulates egg maturation and estrogen production
In males-stimulates sperm development
*release stimulated by GnRH from the hypothalamus

Question 12

Leutinizing hormone (LH)

Answer 12

In females-stimulates ovulation and progesterone production
In males-stimulates testes to produce testosterone
*Release stimulated by GnRH from the hypothalamus

Question 13

Growth hormone (GH)

Answer 13

stimulates cell growth and division in skeletal muscle and bone, stimulates the liver to produce insulin-like growth factor (IGF)
*release stimulated by GHRH from the hypothalamus

Question 14

Prolactin (PRL)

Answer 14

stimulates growth of the mammary gland and milk production

*release stimulated by estrogen from the ovaries

Question 15

Thyroid gland

Answer 15

butterfly shaped gland located in the anterior cervical region
*produces T3, T4, and calcitonin

Question 16

Thyroid hormones T3 and T4

Answer 16

increases cell metabolism, important in normal tissue growth

• produced by follicular cells
• Release stimulated by TSH from the anterior pituitary

Question 17

Calcitonin

Answer 17

decreases blood calcium levels, stimulates osteoblasts, inhibits osteoclast

• produced by C cells of the thyroid gland (parafollicular cells)
• release stimulated by high calcium levels (hypercalcemia)

Question 18

Parathyroid gland

Answer 18

tiny masses found on the posterior side of the thyroid

• parathyroid hormone (PTH) is secreted by chief cells (principal cells) in response to low blood calcium levels (hypocalcemia)
• stimulates osteoclasts to release calcium from bone, stimulates activation of vitamin D leading to increased absorption of Ca2+ in digestive tract, stimulates reabsorption of calcium in the kidneys

Question 19

Adrenal glands

Answer 19

paired, pyramid-shaped organs atop the kidneys-structurally and functionally they are two glands in one (adrenal medulla and adrenal cortex)

Question 20

Adrenal medulla

Answer 20

located in the center of adrenal glands, nervous tissue that acts as part of the sympathetic nervous system

• produces epinephrine (adrenaline) and norepinephrine
• release stimulated by preganglionic sympathetic fibers

Question 21

Adrenal cortex

Answer 21

outer layer of adrenal gland, made of glandular tissue

• synthesizes and releases steroid hormones
• there are 3 zones- zona glomerulosa, zona fasciculata, and zona reticularis

Question 22

Zona glomerulosa

Answer 22

superficial layer of adrenal cortex

*produces mineralocorticoids (chiefly aldosterone)-reabsorption of sodium, secretion of potassium

Question 23

Zona fasciculata

Answer 23

middle layer of adrenal cortex

• produces glucocorticoids (chiefly cortisol)-long term stress response increases blood glucose levels by stimulating synthesis of glucose from protein, increase appetite, suppresses the immune system decreasing inflammation
• release stimulated by ACTH from the anterior pituitary

Question 24

Zona reticularis

Answer 24

deepest layer of adrenal cortex
*produces gonadocorticoids including dehydroepiandosterone (DHEA) an adrogen (hormone that binds to the same receptor as testosterone) to stimulate maturation of hair follicles in women during puberty

Question 25

Pancreas

Answer 25

located posterior to the stomach, functions as both an endocrine and exocrine gland

Question 26

Acinar cells

Answer 26

Exocrine cells that produce digestive enzymes that are secreted into the duodenum

Question 27

Endocrine cells of the pancreas

Answer 27

organized into the islets of Langerhans

Question 28

alpha cells

Answer 28

endocrine cell that produces the hormone glucagon that triggers the breakdown of glycogen in the liver, thus increasing blood glucose levels

Question 29

beta cells

Answer 29

endocrine cells that produce the hormone insulin that increases the uptake of glucose into the cells, thus decreasing blood glucose levels *release stimulated by high blood glucose (hyperglycemia)

Question 30

pineal gland

Answer 30

produces the hormone melatonin that regulates sleep and wake cycles *release stimulated by the hypothalamus during dark hours

Question 31

Thymus

Answer 31

located in upper thoracic cavity over the heart | *produces the hormone thymosin that regulates maturation of T-lymphocytes

Question 32

Ovaries

Answer 32

produce steroid sex hormones * estrogen-stimulates secondary sex characteristics at puberty, plays role in regulating ovarian and uterine cycles * progesterone-works with estrogen to maintain uterine cycle

Question 33

Testes

Answer 33

produces testosterone-stimulates spermatogenesis and secondary sex characteristics at puberty