Unit 5 Exam Review KEY

BIOL 255 SI, Molly

1) The adenohypophysis is the anterior pituitary gland which is made up of glandular tissue and is more part of the endocrine system as it synthesizes and secretes hormones. It is inhibited or stimulated by the hypothalamus.

2) The posterior pituitary is actually part of the brain with neural connections to the hypothalamus which is referred to as the hypothalamic-hypophysealtract. It is the nuclei of the hypothalamus that synthesize oxytocin and antidiuretic hormone(ADH) and these hormones are transported to the posterior pituitary to be released.

3) The anterior pituitary gland secretes seven major hormones and six of the seven are tropic hormones which stimulate other endocrine glands or cells to secrete other hormones.

4) Another anterior pituitary hormone is the thyroid-stimulating hormone (TSH) which is made by the thyrotroph cells and these control thyroid hormone production, which control the metabolic rate. Another hormone is the adrenocorticotropic hormone (ACTH) which is made by the corticotroph cells that control the adrenal cortex’s corticosteroid production.

5) The posterior pituitary gland is made of axons of the hypothalamic neurons and it stores and releases hormones as the axons travel through the infundibulum in the hypothalamic-hypophyseal tract. Hormones are stored in the axon terminals of these neurons in the posterior pituitary and when these neurons are stimulated the axons release the hormone into the bloodstream, so the posterior pituitary is not an endocrine gland as it is the nervous tissue releasing the hormones.

6) Mechanical digestion is the physical act of chewing, mixing and churning of food, while chemical digestion is the enzymatic breakdown of food macromolecules into monomers which can be absorbed from the GI tract into the blood or lymph.

7) The mesenteries consist of a double visceralperitoneum which attach thesmallintestine to the posterior abdominal cavity. The greater omentumis referred to the “fatty apron” draping from the stomach and transversecolon.

8) Hepatic portal vein collects nutrientrich venous blood from thedigestive tract and delivers this blood to theliver for metabolic processing and storage, while the Hepatic Vein drains the liver.

9) The crown of a tooth is covered by enamel which is the hardest substance in the body, while the root of the tooth is covered by cementum which is calcified connective tissue and attaches the root to the periodontal ligament that anchors the tooth in the jaw alveolus and forms the fibrous joint referred to as the gomphosis.

10) Dental caries are the gradual demineralization of enamel anddentin by bacterial action, while Periodontitisis a serious gum disease resulting from an immuneresponse in which results in carving pockets around teeth and dissolving bone.

11) In the stomachchemical digestion of proteins begins and food is churned, and converted to chyme.

12) Epithelial lining contain goblet cells that produce alkaline mucus to protecting epithelial lining from digesting itself. Whereas, the glands of stomach which are the gastric glands of fundus and body contain mucous neck cells that secrete acid mucus, and the parietal cells that secrete HCl and intrinsic factor for VitaminB12 absorption.Chief cells produce pepsinogen which is activated to pepsin by the HCl in stomach and pepsin itself, in which protein is digested intopolypeptides and finally enteroendocrinecells that secrete thehormonesinto the blood.

13) The functions of the Stomach are to hold ingested food, digest food, physically and chemically, to deliverchyme to small intestine, enzymatically digests proteins with pepsin and secrete intrinsic factor required for vitamin B12 absorption.

14) The inner surface of the small intestines contains plicae circulareswhich are deep circular folds of mucosa andsubmucosa which increase surface area 10 fold, which are made up of villi that arefingerlike extensions of mucosa into lumen which also increase surface area 10 fold and finally microvilliwhich are tiny projections of absorptive mucosal cells’plasma membranes into lumen which also increases surface area 10 fold.

15)Thestructural and functional units of kidney are the nephrons, and the blood is filtered in the renal corpuscle which is made up of the glomerulus and the glomerulus capsule, also referred to as the Bowman’s capsule.

16) Every nephron has two capillary beds, the glomerular and peritubular capillaries. Each glomerulus is fed by an afferent arteriole and then drained by an efferent arteriole which are narrower than the afferent. The afferent iswider to accommodate the increased blood pressure so fluids and solutes areforced fromblood through theglomerulus.

17) Filtrate contains no cells, but does contain all plasma components except protein. Water, nutrients, and essential ions are reabsorbed as filtrate and become urine which contains water, metabolic wastes, and unneeded substances.

18) Ureters have atrilayered wall of transitional epithelial mucosa, smooth muscle muscularis and fibrous connective tissue adventitia. The ureters actively propel urine to bladder via peristalsis at intervals of 3to 4 minutes. Ureters enter bladder base through theposterior wall and their distal ends close as bladder pressure increases which preventsbackflow of urine into ureters.

19) In the testes the seminiferous tubules produce sperm and converge to form tubulus rectuswhichconvey sperm to rete testiswhich then leave via efferentductules and enter the epididymis.

20) Interstitial cells produce androgens which in the male is testosterone and the sustentacular cells form the blood testisbarrier.

21) Spermatogenesis takes place in the seminiferous tubules that produce sperm, which are in variousstages of cell division. Mitosis of spermatogonia, forms spermatocytes, then Meiosis forms spermatids from spermatocytes which are haploid and nonmotile and in the final phase, spermiogenesis therethe spermatids lose excess cytoplasm and form atail, becoming sperm.

22) Blood-testis barrier of the Sustentacular cell is made up of tightjunctions that prevent spermantigensfrom getting into theblood, because sperm are not formed until puberty, and their antigens are absent during thymic education. Spermatogoniawhich are recognized as “self”, are influenced by hormonesprompting spermatogenesis.

23) The uterine tubes receive ovulated oocyte and provide the fertilization site then move ovum to uterus via isthmus, then expands distally around ovary forming theampulla.If there is scar tissue in the uterine tubes’ endometrium it may not allow the fertilized ovum to pass to the uterus and an ectopic pregnancy may result.

24) The Corpus luteum is the ruptured follicle after ovulation which produces progesterone and estrogen then degenerates into the corpus albicans.

25) Ampulla ends in the funnel-shaped ciliated infundibulum containingfingerlike projections referred to asfimbriae. The uterine tubes haveno contact with the ovaries. The ovulated oocyte is simply castinto peritoneal cavity and the beating cilia on fimbriae create currentsthat carry the oocyte intouterine tube.

26) The Oocyte is carried to theuterus by peristalsis and ciliaryaction while the nonciliated cells keep oocyte and sperm nourished andmoist.

27) In oogenesis at puberty, one activated primary oocyte produces two haploidcells theSecondary oocyte and the First polar body. The Secondary oocyte is arrested in metaphase II, ovulated, and if fertilized by sperm, the secondary oocyte completes meiosis II and becomesone large ovum referred to as a functional gamete. Then sperm (pro)nucleus fuses with the egg (pro)nucleus and becomes a zygote.