Endocrinology Week 4

What transports glucose from the blood into muscle cells?

GLUT4

What does the pancreas secrete in response to an abundance of blood glucose?

Insulin

T or F: Insulin is a major catabolic hormone

False (it is a major anabolic hormone)

What is the chief organ in charge of maintaining bioenergetics?

Liver

Which gland determines the rate at which our metabolism operates?

Thyroid

What hormone promotes the conversion of glucose to glycogen in the liver?

Insulin

What does the liver convert glucose carbons to for storage?

Cholesterol

What does the liver make using glycogen for storage?

Triglycerides

What transports triglycerides from the liver?

VLDL

What causes the conversion of glycogen to glucose in the liver?

Glucagon

What hormones liberate glucose from muscles?

Epinephrine and norepinephrine

What produces insulin and glucagon?

Islets of langerhans in the pancreas

Which is secreted by alpha cells?

Glucagon

What is secreted by beta cells?

Insulin

What is secreted by delta cells?

Somatostatin

What 3 mechanisms are used to regulate islet cells?

Blood sugar levels

Autonomic nerves

Islet hormones

What type of nerve increases glucagon and decreases insulin?

Sympathetic

What type of nerve increases insulin and decreases glucagon?

Parasympathetic

Why is insulin not active in the sympathetic state?

It would cause sugar to be stored in fat cells

What activates glut transport into muscles during the sympathetic state?

Calcium

Which islet hormones are activated by amino acids in the gut?

Both insulin and glucagon

What is the neutral term for sex gland?

Gonad

What are the two functions of gonads?

Gametogenesis

Sex hormone production/release

What causes gametogenesis in the testes?

FSH

What causes testosterone production in the testes?

LH

Which cells produce testosterone in the testes?

Interstitial cells of Leydig

What is the AKA of male LH?

Interstitial cell stimulating hormone (ICSH)

What is the AKA of the sustentacular cell?

Sertoli

What feeds back on the brain from the sertoli?

Inhibin

Where does developmental testosterone come from in the male fetus?

Adrenal gland

What are primary male sex characteristics influenced by testosterone?

Male genitalia

Descent of testicles

Male sperm

Spermatogenesis

What secondary male sex characteristics are influenced by testosterone?

Distribution of body hair

Thickening of vocal cords

Growth of larynx

Growth of external genitalia

Hypertrophy of muscle mass

T or F: Testosterone is an anabolic hormone

True

Why do people who take testosterone injections have low sperm counts?

Testosterone supplements feed back on the hypothalamus to decrease LH secretions, but are not potent enough to activate spermatogenesis

What are the metabolic actions of testosterone?

Skin thickens

Sebaceous secretions increase (pimples)

Increased protein synthesis throughout the body

Increased muscle mass

Increased BMR

Increased bone matrix

T or F: Testosterone is stronger than estrogen in its anabolic effects and lasts longer

False (testosterone is weaker for longer)

Why does testosterone increase hematocrit?

Increased mitosis of bone marrow stem cells

What type of tissue is the ovarian follicle made of?

secretory epithelium

What determines which ovarian follicle will release an egg?

The one that produces the most estrogen over 14 days

What causes the release of an egg from the ovarian follicle?

Activation of proteolytic enzymes by the LH spike

What is the name of the ovarian follicle after it ovulates?

Corpus luteum

What does the corpus luteum secrete?

progesterone

What does mittelchmerz mean?

Mid-cycle pain (pain of ovulation)

What can cause the secretion of more than one egg during ovulation?

High estrogen levels

T or F: While testosterone is anabolic, estrogen is catabolic

False (they are both anabolic)

Why are estrogen positive breast cancers more dangerous?

Estrogen is a proliferative hormone

What does estrogen cause DNA proliferation of?

Endometrium of the uterus

Mammary glands

Long bones

What enzyme is inhibited by estrogen?

Collagenase

At what time are female athletes most at risk of injury from overtraining?

At the end of menses (estrogen is at its lowest and collagenase activity is highest)

What is the AKA of ovarian estrogen?

Estradiol

What causes the development of secondary female sex characteristics?

Estradiol

What are secondary female sex characteristics?

Breast development including fat

Fat deposition in hips, thighs, buttocks

Proliferation of glandular tissue in breast and endometrium monthly

Softer, thinner sin with increased vascularity compared to males

Female distribution of body hair

What are the metabolic effects of estrogen?

Increased osteoblastic activity

Increased protein deposition

Inhibition of collagenase

Some increase of metabolic rate

Increased sodium absorption by the kidney

Increased HDL activity

Increased fibrinogen

What is the secretory female hormone?

Progesterone

What hormone prepares lactiferous glands for prolactin?

Progesterone

What gives the uterine lining the ability to secrete hormones?

Progesterone

What secretes HCG?

Placenta (trophoblasts)

What is the function of HCG?

Maintains the corpus luteum for 9 months

What are the most significant causes of endocrinopathy?

Ischemia

Benign tumors

What part of the body will ischemia have the greatest effects on endocrine function?

Inside the skull (brain, pituitary gland)

What type of cells are benign tumors made of?

Functional cells

What is a benign tumor made on pinealocytes?

Pinealoma