EXAM 4 digestion and reproduction Flashcards
Fats are also called _______. They break down into what 2 groups when digested?
lipids: triglycerides and cholesterol
Chewing is also called ______. Why do it?
increases surface area for enzymes
What substances does chewing mix food with, and what does each do?
saliva (lubricates), mucus, (lubricates), amylase (begins carb digestion), lingual lipase (attaches for later lipid digestion)
Time from swallow to stomach:
7 sec.
What happens in the stomach, and how long does it take? What happens when it is done?
food mixes with acid and pepsin, 3 hours, then chyme is “spoon-fed” into duodenum
Name the phases of gastric activity.
1) cephalic 2) gastric 3) intestinal
What happens in the cephalic phase of gastric activity?
Thoughts of food lead to a signal travelling through vagus nerve (X) that release hydrochloric acid and start contraction.
What happens in the gastric phase of gastric activity?
pH goes up and walls stretch, both signalling more HCl secretion, more pepsin secretion, and more contraction
What is the pH of an empty stomach?
2.0
What happens in the intestinal phase of gastric activity?
controlled emptying (spoon-feeding) into duodenum
Bile is made where? Stored where?
liver: gall bladder
Draw the busy intersection.
duodenum: include chyme from stomach, HCO3- from pancreas, digestive enzymes from pancreas, and bile
Chyme is made up of:
partly digested carbs with their salivary amylase, proteins with the pepsin that digests proteins, fats, with lingual lipase and bile that digest fats, plus acid
Name the pancreatic enzymes and the part of chyme they digest.
pancreatic amylase (carbs), pancreatic protease (proteins), pancreatic lipase, HCO3-
After passing through the doudenum, what is the progress of digestion?
All but few chunks are broken into particles.
What is added for carbohydrates to chyme in the duodenum? What does this cause?
Glucose-dependent Insulinotropic peptide: causes pancreas to secrete insulin.
What is added for protein and fats to chyme in the duodenum? What does this cause?
cholecystokinin; causes 1) gallbladder contraction, 2) relaxation of hepatopancreatic sphincter, 3) pancreas to release digestive enzymes, 4) pyloric sphincter contraction 5) signals sateity to the hypothalamus
What is added for acid to chyme in the duodenum? What does this cause?
secretin; causes 1) pancreas to release HCO3- (which neutralizes some acid) and relaxes hepato-pancreatic sphincter
Why don’t carbs make you feel full like fats and proteins?
They don’t cause secretion of cholecystokinin, which contracts the pyloric sphincter, slowing stomach emptying, and also signal satiety to the hypothalamus.
What does the suffix “trophic” mean?
all it does is cause another substance to be secreted
Draw a segment of small intestine with layers
include villi, capillaries, mucosa, submucosa, muscularis mucosa. muscularis externa, and serosa… and the capillaries send nutrient-rich blood to the liver
describe the condition of absorbable food in the small intestine
glucose, amino acids and a few still connected disaccharides and dipeptides
What is VIP and what does it do?
vasoactive intestinal peptide makes villi capillaries dilate to accept nutrients
Serosa is aka
viseceral peritoneum
WHat is the role of dead villi cells in intestine.
secrete brush border enzymes that break up still connected disaccharides and dipeptides
muscularis externa does this
contracts to move food along
role of visceral peritoneum
covers internal organs
this enzyme breaks down lactose- what does it break it down into? What breaks down sucrose, and what are the results.
lactase, breaks it into glucose and galactose
sucrase, breaks sucrose into glucose and fructose
Why do fats have special digestive chemicals? What makes it possible to digest fat?
fats are not water soluble, but the enzymes to process it are. Bile (a detergent) makes it possible todigest fats.
name for the tiny spheres that bile breaks fat into so lipase can access it
micelles
name the fat soluble vitamins
K, A, D, E
What happens to micelles before they are sent to the liver?
epithelial cells package micelles into chylomicrons, which go into lymphatic vessels because they are too big for capillary pores, and the lymphatic system takes them to the thoracic duct
What is the job of insulin?
makes sugar usable to cells
Where are the hunger and satiety centers located?
hypothalamus
draw the feed and satiety centers and the 5 input types
pic 3, ghrelin, blood sugar, CCK, insulin, full stomach
What are 2 actions of ghrelin?
stimulates hunger center in hypothalamus and promotes growth hormone secretion
What is leptin? Where is it made? What is its effect on metabolism?
a peptide hormone that is secreted by adipose tissuethat turns on the satiety center and turns off the feed center. It speeds metabolism.
What effect does very fast weight loss have on leptin? Why is slow weight loss better?
Metabolic slowing happens with quick weight loss- you have leptin that has no receptors. With slow weight loss, your body will reduce its leptin receptors so there are as few receptors as there is leptin.
Another word for insulin insensitivity.
diabetes
What does a type II diabetic lack?
insulin receptors
This causes insulin receptors to be deleted like Facebook friends who share TMI.
excess sugar and insulin
Too much adipose tissue means too much ______ for receptors to handle.
leptin
draw the picture of the set point
include increased and decreased body fat, increased/decreased leptin, increased/decreased basal metabolic rate, less/more eating
What is the reproductive cell (gamete) made by the testis, and what is the primary hormone secreted? What is the reproductive cell of the ovary, and what are the main hormones secreted?
Testis makes spermatazoa and testosterone. Ovary makes oocytes, and the hormones estradiol and progesterone.
What is the first organ that starts the chain of reproductive hormone secretion? What hormone starts the chain?
hypothalamus secretes GnRH, Gonadotropin Releasing Hormone
What does GnRH trigger?
GnRH triggers the Anerior Pituitary to release LH and FSH
What is LH? What is FSH? What organs do they affect?
Luteinizing Hormone and Follicle Stimulating Hormone both affect the gonads (ovary and testis)
What cell in the testis is affected by LH? What cell is affected by FSH?
LH triggers Leydig cells to make testosterone, and FSH triggers Sertoli cells to promote spermatogenesis
What cell in the ovary is affected by LH? What cell is affected by FSH?
LH triggers Theca cells to produce weak androgens, and FSH triggers granulosa cells to make P450 aromatase to convert weak androgens to estrogens
What is liquid filled part of an ovarian cell that gets very large in a tertiary follicle?
the antrum
Prostaglandins cause ____ muscle contractions to scoot sperm down the ejaculatory tract.
smooth
Why is there fructose in seminal fluid?
nutrients for spermatozoa
Why are there bases in seminal fluid?
neutralize acidic vagina
What % of seminal fluid come from the bulbourethral gland? What is another name for this gland?
5% from Cowper’s gland
60% of seminal fluid is produced here
seminal vesicles
What 3 landmark structures are the same in the sagittal pubic region in male and female?
pubic symphysis, urinary bladder, rectum
What is the function of the epididymus?
stores spermatozoa and capacitates (matures) them
30% of seminal fluid is produced here.
prostate gland
What is the structure in the testis where spermatogenesis occurs?
seminiferous tubules
What is the muscular structure that allows you hold hold in urine?
urogenital diaphragm
Of the three large tubules that run the length of the penis, which are the 2 erectile tubules? What is the 3rd tubule?
corpus cavernosa are erectile, and the corpus spongiosum is not
What do Sertoli cells do for spermatozoa?
deliver nutrients, remove toxins, form a “blood-testis” barrier, remove waste, promote spermatogenesis (chemically)
What is the difference between spermatocytes and spermatogonia?
spermatocytes are haploid (23 chromosomes or “n”) spermatogonia are diploid (46 chromosomes or “2n”)
What sheds and rebuild in the menstrual cycle?
endometrium
Name the follicular stages.
1) primordial follicle, 2) primary, 3) secondary, 4) tertiary, 5) corpus luteum, 6) corpus albicans
A surge in what hormone triggers ovulation?
LH, Luteinizing Hormone
What happens at day 10 of ovarian cycle?
Estradiol is high enough to trigger a positive feedback loop that increases LH, FSH, and GnRH.
Progesterone and estradiol. Which is for mating and which is for pregnancy?
Estradiol is for mating and progesterone is for pregnancy.
What structure is needed to keep progesterone levels igh enough to maintain pregnancy?
Corpus luteum
What is the placenta’s version of Leuteinizing Hormone?
HCG, human chorionic gonadotropin
What does oxytocin increase do?
makes uterus more contractile
What does progesterone do with regard to uterine contractions?
prevents them
What does relaxin do?
in the presence of estrogen it softens connective tissues in the pelvis/cervix
What does human placental lactogen do?
prepares mammary glands to lactate and intereferes with insulin so the mother’s blood sugar is higher for the fetus
