224 Lecture Final Flashcards
Digestive system
Organ system that processes food, extracts nutrients, and eliminates residue
Examples of chemical digestion
Polysaccharides into monosaccharides
Proteins into amino acids
Fats into monoglycerides
Nucleic acids into nucleotides
Accessory organs
Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
What is saliva composed of
Salivary amylase Lingual lipase Mucus Lysozyme Immunoglobulin A Electrolytes
Swallowing center
Coordinated by medulla oblongata through nerves of face
Started by trigger in brain
Function of the stomach
Mechanically breaks up food, liquefies it, and begins chemical digestion of protein and fat
Cells and their function
Mucous cells
Parietal cells
Chief cells
Mucous cells
Secrete mucus
Protect stomach from its own acid
Parietal cells
Secrete hydrochloric acid
Chief cells
Secrete gastric lipase and pepsinogen
Phases of gastric activity
Cephalic phase
Gastric phase
Intestinal phase
Cephalic phase
Stomach controlled by brain
Gastric phase
Stomach controlling itself
Intestinal phase
Stomach being controlled by small intestines
Function of the liver
Secretes bile
Path of bile
Secreted into duodenum
Regions of the small intestines
Duodenum
Jejunum
Ileum- longest
Protein digestion
Pro teases (peptidases)- enzymes that digest proteins
Emulsification droplets
Broken down further by bile, lecithin, and agitation produced by intestinal segmentation
Role of intestinal microbes
Gut microbiome
-Bacteria digest cellulose
-Help in synthesis of vitamins B and K
Flatus
-Flatus is intestinal gas and a lot of it is swallowed air, but bacteria add to it
- bacteria are involved in the formation of prt of the feces
Body weight
Weight is stable of energy intake equals energy output
Gut-brain peptides
Two way chemical signals between gastrointestinal tract and brain
Short vs long term regulators
Short term: -peptide Y(PYY) -cholecystokinin (CCK) Long term: -insulin
Macronutrients
Must be consumed in relatively large quantities
Water, carbs, lipids, and proteins
Micronutrients
Only small quantities are required
Vitamins and minerals
Complete proteins
High quality complete proteins- provide all essential amino acids
-animal proteins- meat, eggs, dairy
Minerals vs vitamins
Minerals- inorganic elements
Vitamins- organic compounds
Vitamin deficiencies
Vitamin A deficiency- night blindness; dry skin, hair, and conjunctiva; cloudy corneas, and increased incidence of infections
-most common vitamin deficiency
Body temperature (shell temperature)
Oral cavity and skin
Thermoregulation
Heat-losing mechanisms
- cutaneous vasodilation- increases blood flow close to the body’s surface and promotes heat loss
- •if necessary, triggers sweating
Heat exhaustion
From severe water and electrolyte loss
From exposure to excessive heat
Primary sex organs (gonads)
Testis and ovaries
Gametes- sperm and egg
Secondary sex organs
Male- system of ducts, glands; penis delivers sperm cells
Female- uterine tubes, uterus, and vagina receive sperm and harbor developing fetus
Sex of child
XY- male
XX- female
Determined by sperm
Descent of the testis
Descent of the testes begins as early as 6 weeks
Stimulated by the presence of testosterone
Spermatic ducts
- transport sperm from testis to the urethra
Accessory glands
Seminal vesicles
-forms 60% of semen
Prostate
-thin milky secretion forms 30% of semen
Enlarged prostate
Benign prostatic hyperplasia- non cancerous enlargement of the prostate
- compresses urethra and obstructs flow of urine
Hormones
LH- stimulates interstitial cells to secrete testosterone
- testosterone stimulates development of the secondary sex characteristics, spermalogenesis, and libido
Inhibit- nurse cells- suppresses FSH output from the pituitary, reducing sperm production
-adjusts rate of sperm production (spermalogenesis) without affecting testosterone secretion
Spermatogenesis
Process of making sperm
- Germ cells divide
- Reduction of chromosomes (1/2)
- Shuffling of genes- genetic variation
Melosis- recombined genes, produces four haploid cells, with 23 chromosomes each, that will become sperm (gametes)
Composition of semen
Semen (seminal fluid)
- 60% seminal vesicle fluid, 30% prostatic fluid, and 10% sperm
Neural control
Penis is richly innervated
- innervated by the internal pudendal
Internal genitalia
Ovaries, uterine tubes, uterus, and vagina
Female reproductive tract
Uterine tube- where ovulated egg is released, fertilization occurs
Puberty (female)
Estrogens are feminizing hormones with widespread effects on the body
The earliest sign of puberty is the inset of breast development
Menstrual cycle
The cyclic changes in the uterus determined by shifting hormonal changes
-divided into four phases
Resolution
Women do not have refractory period: may quickly experience additional orgasms
Human chorionic gonadotropin (HCG)
Pregnancy detection hormone
-stimulates growth of corpus luteum
Stages of labor
- dilation- longest stage
- Expulsion
- Placental stage
