Exam 4 Flashcards
What are the 4 tissue layers of the digestive tract, from innermost to outermost?
Mucosa, submucosa, muscularis externa, serosa
What is the mucosa layer of the digestive tract?
The innermost, it lines the lumen and contains MALT for lymphatic function and capillaries for absorption
What is the submucosa layer of the digestive tract?
Loose connective tissue containing blood vessels, lymphatic vessels, and nerves. Mucus-secreting glands dump mucus into the lumen
What are the layers of the muscularis externa of the digestive tract?
Inner circular layer and outer longitudinal layer
What is the inner circular layer of the muscularis externa?
Contains sphincters which regulate the passage of material through the tract
What is the outer longitudinal layer of the muscularis externa?
Motility propels food and residue through the tract
What is the serosa layer of the digestive tract?
Outermost. Areolar tissue
What are dentition?
Teeth
What are the regions of the tooth?
Crown, root, neck (and root canal)
What is the crown of a tooth?
The portion above the gum
What is the root of a tooth?
The portion below the gum
What is the neck of a tooth?
The point where the crown, root, and gum meet
What is a root canal?
A canal leading from the roots to the pulp cavity in the crown
What are the extrinsic salivary glands?
Parotid, submandibular, and sublingual
Components of saliva?
97-99.5% water, salivary amylase, lingual lipase, lysozyme, and IgA
What does salivary amylase do?
It’s an enzyme that begins starch digestion in the mouth
What does lingual lipase do?
Digests fat
What do lysozyme and IgA do?
Enzymes that kill bacteria
What is the blood sugar between and after a meal?
Between - hypoglycemic
After- hyperglycemic
What is the uvula?
Protrusion of the soft palate hanging in the back of the throat
What is the epiglottis?
A flap which covers the trachea during swallowing so food doesn’t enter the airway
What are pharyngeal tonsils?
AKA the adenoids
What are gastric pits?
Filled with parietal cells which produce hydrochloric acid (or HCl) for converting pepsinogen into pepsin, which digests proteins, and intrinsic factor, for absorbing vitamin B12
What is the pathway of G cells of the stomach?
G cells stimulate chief cells, food comes to stomach, elevated pH comes to gastric pits, stimulates G cells as stomach stretches out
Difference between ingestion and digestion?
Ingestion is the intake of food, digestion is the mechanical and chemical breakdown of food into a form usable by the body
What is the difference between mechanical and chemical digestion?
Mechanical physically breaks food down, chemical degrades molecular structure and follows mechanical digestion
What are the 3 main macromolecules?
Carbs, proteins, and fats
What do carbs break down into?
Monosaccharides
What do proteins break down into?
Amino acids
What do fats break down into?
Monoglycerides and fatty acids
What has to be done to polysaccharides?
They have to be broken down into monosaccharides
What are the 3 phases of the gastric process?
Cephalic phase, gastric phase, and intestinal phase
What happens during the cephalic phase of the gastric process?
The stomach controlled by the brain - responds to sight, smell, taste, and thought of food using acetylcholine
What happens during the gastric phase of the gastric process?
Swallowed food and semi-digested protein activate gastric activity because food stretches the stomach
What happens during the intestinal phase of the gastric process?
The stomach controlled by the small intestine. Duodenum responds to arriving chyme and moderates gastric activity via hormones and nervous reflexes
What sphincter separates the large intestine and small intestine?
The ileocecal sphincter
Parts of the large intestine?
Ascending, transverse, and descending
Purpose of HCl?
Converts pepsinogen to pepsin, which comes from chief cells
What do chief cells secrete?
Pepsinogen and intrinsic factor
What does a lack of intrinsic factor cause?
Pernicious anemia
Different regions of the stomach?
Cardia, near tube leading in. Fundus, at top of stomach. Body, the majority. Pyloris, at bottom of stomach
What is mastication?
Chewing
Difference between hard and soft palate?
Hard is anterior. Soft is posterior, contains uvula, and helps retain food in mouth
Digestive organs?
Mouth, pharynx, esophagus, stomach, small intestine, large intestine
Accessory organs of the digestive system?
Teeth, tongue, salivary glands, liver, gallbladder, pancreas
Function of mouth?
Ingestion and chewing and chemical/mechanical digestion
Function of pharynx?
Allows entrance of air from nasal cavity to larynx where swallowing occurs
What is deglutition?
Swallowing
Function of the esophagus?
Brings food into stomach
Function of stomach?
Mechanically break up food particles (using oblique muscle), liquefy food and begin chemical digestion of protein and fat
What is chyme?
Soupy or pasty mixture of semi-digested food in the stomach
Regions of the small intestine?
Duodenum - top
Jejunum - middle
Ileum - bottom
Function of small intestine?
Chemical digestion and nutrient absorption
What is peristalsis?
Movement of contents towards colon
What is segmentation?
Churning and mixing for digestion
Function of large intestine?
Water reabsorption. Squeezes it out to turn the remnants into feces
What are haustral contractions?
Every 30m, they squeeze water out of chyme
What are mass movements?
Occurring 1-3 times a day, peristaltic waves moving food toward the rectum
Teeth function?
Mechanically digest food
Tongue function and makeup?
Manipulation of food. Nonkeratinized stratified squamous epithelium
Salivary glands function?
Helps digest starches and fats and kill bacteria
Liver functions?
Stores food. Breaks down stored glycogen to release glucose into blood between meals. Synthesizes bile. Secretes albumin, lipoproteins, clotting factors, and angiotensinogen into blood
Gallbladder functions?
Stores and concentrates bile
What does bile do?
Aid in fat digestion and absorption
Pancreas function?
Acini release a secretion into the pancreatic duct which is enzymes which digest starch and fat
What is ingestion?
Intake of food
What is digestion?
Mechanical and chemical digestion of food into a form usable by the body
What is absorption?
Uptake of nutrient molecules into epithelial cells of digestive tract, and then blood and lymph. Moves food from the outside of the body to the inside of the body
What is compaction?
Absorbing water and consolidating indigestible residue into feces
What is defecation?
Elimination of feces
What is the lesser omentum?
It attaches the stomach to the liver
What is the greater omentum?
It covers the small intestines like an apron
What nutrients do not require digestion?
Vitamins, free amino acids, minerals, cholesterol, water
A 38-year-old male is upset about his low sperm count and visits a “practitioner” who commonly advertises his miracle cures of sterility. The practitioner is a quack who treats conditions of low sperm count with mega doses of testosterone. Although his patients experience a huge surge in libido, their sperm count is even lower after hormone treatment. Explain the surge in libido and the lower sperm count.
1) Sperm is produced when gonadotropin hormone-releasing hormone stimulates the anterior pituitary to secrete FSH and LH. 2) While it is true that testosterone is a part of the process of sperm production, FSH and LH are also needed in this process. 3) Therefore, prescribing only testosterone will not serve to raise sperm count. 4) It will, however, raise libido as described when on its’ own as this is a function of testosterone. 5) This excess testosterone also reduces the secretion of gonadotropin hormone-releasing hormone, inhibiting the release of FSH and LH, and therefore preventing the production of sperm.
Explain how the 28-day birth-control pill works. How does the pill affect the female menstrual cycle and how does it affect the hormones of the reproductive system?
1) Birth controls have progesterone and estradiol which are taken for 21 days, followed by 1 week of placebo pills with no hormones. 2) The placebo pills trigger breakthrough bleeding due to the drop in hormones. 3) Having higher levels of estrogen and progesterone for 21 days due to the hormonal pills overrides the hormonal cycling that occurs naturally during the menstrual cycle. 4) The pills suppress release of FSH and LH, making the body believe the woman is pregnant and therefore suppressing the menstrual cycle. 5) This prevents ovulation, preventing menstruation as well
Pathway of sperm?
Seminiferous tubules -> epididymis -> vas deferens -> ejaculatory duct -> urethra -> penis
4 divisions of intercourse?
Excitement, plateau, orgasm, resolution
What happens during excitement of a male?
Vasocongestion, erection of penis, myotonia, increase in heart and respiratory rate and blood pressure, bulbourethral glands secrete their fluid
What does bulbourethral gland fluid do?
Lubricate head of penis and reduce acidic environment of the urethra for sperm to survive