Unit 4 Review Questions Flashcards
List the endocrine organs.
hypothalamus, pituitary, thyroid, parathyroid, thymus, adrenal glands, pancreas, ovaries, and testes.
What are the differences between endocrine and exocrine glands?
endocrine glands secrete hormones into the bloodstream, exocrine glands secrete their product on the outside or the body or in the lumen of an organ.
What endocrine organs contain both endocrine and exocrine glands?
Pancreas, ovaries, and testes.
What are the two types of hormones?
amino acid-based hormones (peptides, amines, and proteins)
steroids (gonadal and adrenocortical)
What makes a cell a target for a hormone?
It has the receptor for the hormone
How do intracellular hormone receptors function, and what type of hormone activates them?
Hormone crosses the cell membrane because it is lipid soluble (gonadal, adrenocortical, and thyroid). Bind to the receptor inside the cell and forms a hormone-receptor complex. This binds to a segment of DNA and turns on the transcription of a target gene to create proteins that alter cell activity.
How do cell membrane hormone receptors function and what type of hormone activates them.
Cell membrane receptors attach to water-soluble proteins (amines, peptides, and proteins). The binding activates the G protein in the cell, which activates adenyl cyclase. Adenyl cyclase catalyzes the conversion of ATP to cAMP. cAMP activates protein kinases which hydrolyze ATP to ADP. Free phosphate phosphorylates proteins, activating them which changes cell activity.
How are blood levels of hormones controlled?
Negative feedback systems.
Discuss the 3 stimuli that cause hormone release.
humoral stimuli: extracellular concentrations of solutes
neural stimulus: direct neural communication to glands
hormonal stimulus: gland stimulated by another hormone
Describe the structure and function of the posterior pituitary (neurohypophysis) and how it interacts with the hypothalamus.
Connected to the hypothalamus by the hypothalamic-hypophyseal tract (group of axons). Stores and secretes hormones made by the hypothalamus. Action potentials from the hypothalamus cause release of hormones.
Discuss the stimuli, sites of production, targets, and effects of oxytocin.
Created in the paraventricular nucleus in the hypothalamus. Positive feedback cycle. Cervical stretching causes the release of this hormone which causes uterine smooth muscle contraction. Breastfeeding causes the release, which causes smooth muscles in the mammary glands to contract and eject milk. Also acts on the brain and is involved in emotional bonding and intimacy.
Discuss the stimuli, sites of production, targets, and effects of ADH.
Created in the supraoptic nucleus. Dehydration/high blood osmolarity/low BP causes the release of ADH, which act on the principal cells in the collecting ducts of the kidneys to create aquaporins and reabsorb water into the blood.
Describe the structure and function of the anterior pituitary (adenohypophysis) and the hypophyseal portal system.
Made of glandular tissue, hypothalamic neurons secrete releasing or inhibiting hormones to the blood of the hypophyseal portal system which brings the hormones to the anterior pituitary.
Discuss the stimuli, hypothalamic regulation, secreting cells, targets, and effects of growth hormone.
Stimulated by growth hormone releasing hormone secreted by the hypothalamus. Secreted by somatotrophs. Affects almost all cells in the body. Promotes lipolysis and switches body to fatty acid usuage for energy, glucose sparing. Liver breaks down glycogen to glucose. Increases protein synthesis, cellular proliferation, cell mitosis, epiphyseal plate growth, and increase in skeletal muscle size. Indirect effect is liver releasing insulin-like growth factor. This causes a negative feedback for GH production and causes the hypothalamus to produce growth hormone inhibiting hormone.
Stimulation of growth hormone-releasing hormone
low GH, low blood glucose, deep sleep, and exercise
