PHYSIO FINAL EXAM

Identify the hormones that increase or decrease blood glucose and those that stimulate lipogenesis or lipolysis

- A rise in plasma glucose concentration stimulates insulin and inhibits glucagon secretions -Amino acids stimulate the secretion of both insulin and glucagon -Insulin promotes the uptake of blood glucose into skeletal muscle and other tissues. This lowers the blood glucose conc. -Glucagon stimulates glycogenolysis in the liver, gluconeogenesis, lipolysis, and ketogenesis.

Explain the functions of adipose tissue and the dangers of obesity

-Adipose tissue, or fat, is an anatomical term for loose connective tissue composed of adipocytes. Its main role is to store energy in the form of fat, although it also cushions and insulates the body -it serves as an endocrine organ capable of synthesizing a number of biologically active compounds that regulate metabolic homeostasis -Obesity risk factors for cardiovascular disease, diabetes, gallbladder disease, and some cancers.

Know the different phases during digestion (cephalic, gastric, intestinal)

-Cephalic phase: control by brain via vagus nerve; stimulates ECL (major response), chief cells, and parietal cells;Lasts for the first 30 minutes of a meal. -Gastric phase: triggered by arrival of food into stomach; Gastric secretion is stimulated by stomach distention and the chemical nature of the chyme; Positive feedback occurs; as more proteins are broken down more secretions are released to break them down. -Intestinal phase: inhibition of gastric activity when chyme enters the small intestine; slows the movement of chyme into the duodenum to allow more time to digest/absorp; Stretch when food enters the duodenum stimulates a neural reflex that inhibits gastric stimulation via vagus nerve; the presence of fat stimulates the duodenum to make enterogastrone which inhibits gastric func.

Know the functions of the liver

-Detoxication of blood -Carbohydrate metabolism -Lipid metabolism -Protein synthesis -Secretion of bile

Know how sex is determined (XX or XY)

-Each zygote gets 23 chromosomes from mom and 23 from dad -22 pairs are autosomal chromosomes -The last pair are the sex chromosomes (XX or XY) -Males can pass on either an X or Y chromosome -The sex of a child is determined by the contributing sperm

Identify the brain regions involved in hunger and describe the regulation of hunger by specific neurotransmitters and hormones.

-Eating behavior is regulated, at least in part, by the hypothalamus. -A variety of NT have been implicated in the control of eating behavior. These include the endorphins, norepinephrine, serotonin, cholecystokinin, and neuropeptide Y.

Distinguish between the caloric and anabolic requirements of the diet

-Excess calorie intake (regardless of source)= storage of fat; positive energy balance -Avg male: 2,900 kcal/day -Avg female: 2,100 kcal/day -Weight is lost when fewer calories are consumed than needed; negative energy balance -The body can adjust metabolic requirements which may make weight gain or loss difficult -Food also supplied the raw materials for synthesis reactions - collectively termed anabolism -

Know the hormones involved in parturition and lactation

-Lactation: prolactin from the pituitary gland stimulates the production of milk, proteins, casein, and lactalbumin -Labor/Parturition: stimulated by oxytocin and prostaglandins

Where does carbohydrate digestion start? Name the first enzyme used

-Most carbohydrates are ingested as starch or sugars such as sucrose and lactose. -Starch digestion begins in mouth with salivary amylase;

Where are HCl and HCO3- secreted?

-Parietal cells secrete HCl and intrinsic factors. These cells are located in the gastric glands found in the lining of the fundus and in the cardia of the stomach -HCO3 is produced within the parietal cells by dissociation of carbonic acid. Much of the HCO3 that enters the blood eventually returns to the GI tract in the alkaline pancreatic juice that enters the duodenum, and some is filtered into urine.

What are segmentation, peristalsis, and mass movements?

-Segmentation: major contractile element of the small intestine; churning and mixing while moving forward -Peristalsis: wave-like, one way movement through the tract -Mass movements??***

What is trypsinogen and pepsinogen?

-The inactive form of trypsin, called trypsinogen, is activated within the small intestine by the catalytic action of the brush border enzyme enterokinase (which converts trypsinogen to active trypsin). -Chief cells secrete pepsinogen. The gastric mucosa secretes the inactive enzyme pepsinogen. Pepsinogen ezymes partially digest each other. Converted into pepsin by the gastric acid.

What are plicae, and what is their function?

-The mucosa and submucosa form large folds called plicae circulares. -Absorption occurs at a rapid rate as a result of extensive foldings which increase absorptive surface area

Know the functions of the placenta

-The placenta secretes both steroid hormones and proteins hormones -serves as an interface between the mother and the developing fetus -Attach the fetus to the uterine wall -Provide nutrients to the fetus -Allow the fetus to transfer waste products to the mother's blood

Describe the effects of growth hormone on the metabolism of lipids, glucose, and amino acids AND explain how growth hormone stimulates skeletal growth

-The secretion of growth hormon is increased during fasting and during absorption of a protein meal. Growth hormone exhibits both the anabolic and catabolic effects. Growth hormone is involved in promotion of protein synthesis similar to insulin. - The stimulatory effects of growth hormone on skeletal growth results from stimulation of mitosis in the epiphyseal growth plates of cartilage in the long bones of children and adolescents.

Know the cyclic changes in the endometrium

-The term menstruation is used to indicate the periodic shedding of the stratum functionale of the endometrium, which becomes thickened prior to menstruation under the stimulation of ovarian steroid hormones.

What are the placental hormones?

-chroionic gonadotrophin (hCG) -Chorionic somatomammotropin (hCS) -Growth hormone variant (hGH-V) -Progesterone -Estrogen

What are the 4 phases of the human sexual response?

1) Excitation: characterized by increased muscle tone, vasocongestion of sexual organs, also called arousal 2) Plateau: continued vasocongestion 3) Orgasm: contraction of the uterus/vagina and male ejaculatory organs 4) Resolution: body returns to pre excitation conditions

Know the functions of the digestive system

1) Motility: this refers to the movement of food through the alimentary tract through the process of ingestion, mastication, deglutition, peristalsis, and segmentation. 2) Secretion: this includes both exocrine and endocrine secretions 3) Digestion: this refers to the breakdown of food molecules into their smaller subunits, which can be absorbed 4) Absorption: this refers to the passage of digested end products into the blood or lymph. 5) Storage and elimination: temporary storage and subsequent elimination of undigested food molecules 6) Immune barrier: simple columnar epithelium with tight junctions prevents swallowed pathogens from entering the body; immune cells in CT of the tract promote immune responses.

Know the functions of the different organs in digestion

Alimentary organs: -oral cavity -pharynx -esophagus -stomach -small intestine -large intestine Accessory digestive: organs: -teeth -tongue -salivary glands -liver -gallbladder -pancreas

What is bile? Where is it produced and secreted?

Bile: is a yellowish green fluid containing bile salts, bilirubin, cholesterol, and other compounds. Stored in the gallbladder. Bile is produced by the liver. The liver is then stimulated to secrete more bile by secondary bile acids that return to the liver from the intestine via the hepatic portal vein.

What are chief cells and what do they secrete?

Chief (or zymogenic) cells: which secrete pepsinogen, an inactive form of the protein digesting enzyme pepsin;

Know the neurological implications of the swallowing reflex

Deglutition: or swallowing is divided into three phases: oral, pharyngeal, and esophageal. Swallowing is a complex activity that requires the coordinated contractions of 25 pairs of muscles in the mouth, pharynx, larynx, and esophagus. The oral phase is under voluntary control, while the pharyngeal and esophageal phases are automatic and controlled by the swallowing center in the brain stem.

Describe how the secretions of insulin and glucagon change during periods of absorption and periods of fasting. How are these changes in hormone secretion produced

During absorption of a meal, the glucose of the blood moves from small intestine to liver and the beta cells of pancreas are stimulated to release insulin. High blood glucose levels and release of insulin depress the glucagon levels. Insulin release triggers different processes and promotes the storage of nutrients.

What does the pancreas produce?

Endocrine function: pancreatic islets secrete the hormones insulin and glucagon into the blood Exocrine gland: the pancreas secretes pancreatic juice through the pancreatic duct into the duodenum.

Identify the free radicals and reactive oxygen species, and describe their significance

Free radicals: are molecules with unpaired electrons; can have mutating actions on body. The major free radicals are referred to as reactive oxygen species (ROS) or reactive nitrogen species -Reactive oxygen species: produced in electron transport chain; superoxide radical (O2), hydroxyl radical (HO)

What is the function of the large intestine?

Functions: -Absorption of water, electrolytes, vitamin K, and some B vitamins -Production of vitamin K and B vitamins via microbial organisms -Storage of feces

What are G cells and what do they secrete?

G cells: a cell in the gastric gland; secrete the hormone gastrin into the blood.

What is hermaphroditism and Pseudohermaphroditism?

Hermaphroditism: a condition in whcih ovarian and testicular tissue is present in the body. Pseudohermaphrodites: individuals with either testes or ovaries, but not both, who have accessory sex organs and external genitalia that are incompletely developed or that are inappropriate for their chromosomal sex.

How are fats absorbed?

In the small intestines bile emulsifies fats while enzymes digest them. The intestinal cells absorb the fats. Long-chain fatty acids form a large lipoprotein structure called a chylomicron that transports fats through the lymph system

What is intrinsic factor? Know the importance between intrinsic factor and anemia

Intrinsic factor: secreted by the parietal cells; is required for the intestinal absorption of vitamin B12. Vitamin B12 is necessary for the production of RBC in the bone marrow. This causes pernicious anemia

Explain how the metabolic rate is influenced by exercise, ambient temperature, and the assimilation of food

Metabolic Rate: measured by amount of heat generated or amount of O2 consumed per minute. -Increased by exercise or eating -Body temperature is an important factor, influences reaction rate.

Know the histology of the different layers of the GI tract

Mucosa: absorptive and major secretory layer, consists of a simple columnar supported by the lamina propria. External to lamina propria is a thin layer of smooth muscle called the muscularis mucosae. Submucosa: relatively thick submucosa is a highly vascular layer of CT. Absorbed molecules enter into blood and lymphatic vessels of the submucosa. Also contains glands and nerve plexuses Muscularis: responsible for segmental contractions and peristaltic movement through the alimentary tract. Has an inner circular and an outer longitudinal layer of smooth muscle. Myenteric plexus located in between the two layers. -Serosa: completes the wall of the alimentary tract; consists of areolar CT covered with a layer of simple squamous

Describe the mechanisms by which the secretion of parathyroid hormone and of calcitonin is regulated.

Parathyroid hormone promotes an elevation in blood Ca2+ by stimulating resorption of the calcium phosphate crystals from bone and renal excretion of phosphate. -Whenever the plasma concentration of Ca2+ begins to fall, the parathyroid glands are stimulated to secrete increased PTH taht work to raise the blood Ca2+ back to normal levels

Where does nutrient absorption primarily occur?

Small intestines: absorption of nutrients; sugars, lipids, amino acids, calcium, and iron absorbed in duodenum and jejunum. Bile salts, vitamin B12, water and electrolytes in ileum; very rapid due to villi and microvilli (increase SA)

Know spermatogenesis and oogenesis

Spermatogenesis: the production or development of mature spermatozoa. Oogenesis: the production or development of an ovum

Know the different hormones that are involved in sexual maturation

Testosterone, estrogen, and progesterone

What is digestion

The breakdown of food molecules into their smaller subunits, which can be absorbed.

What is fertilization?

The fusion of an ovum and spermatozoon

Know the relationship between the ovarian and menstrual cycles

The ovarian cycle governs the preparation of endocrine tissues and release of eggs, while the menstrual cycle governs the preparation and maintenance of the uterine lining

What is implantation?

The process by which the blastocyst attaches itself to and penetrates the endometrium of the uterus

Explain the actions of thyroxine on the basal metabolic rate. Why do people with hypothyroidism have a tendency to gain weight, and why are they less resistant to cold stress?

Thyroxine increases production of metabolic heat required for cold adaption; increase basal metabolic rate (BMR). -Most of the extra weight gained in hypothyroid individuals is due to excess accumulation of salt and water.

Describe the causes of hyperglycemia in a person with type 2 diabetes. How may weight loss help to control this condition?

Type 2 diabetes mellitus occurs as a result of a relative tissue insensitivity to insulin and inadequate insulin secretion; this condition is aggravated by obesity and improved by exercise. -Exercise makes skeletal muscle cells more sensitive to insulin

List the water-soluble and fat-soluble vitamins and describe some of their functions

Water-soluble Vitamins: -Thiamin (B1): needed to convert pyruvate to acetyl CoA -Niacin (B3) and riboflavin (B2): needed to make FAD and NAD coenzymes that act as H carriers in cell respiration -Pyridoxine (B6): needed for amino acid metabolism -Vitamin C: antioxidant; inactivated free radicals Fat Soluble Vitamins: -Vitamin E: strong antioxidant; helps mitigate inflammatory response -Vitamin K: needed to make clotting factors -Vitamin D: needed for calcium absorption, tissue differentiation, and regulate gene expression -Vitamin A: involved in embryonic development, T cell activity, dim light vision, and epithelial cell development/function