Test 4 Ap Flashcards
Stages of digestion
Ingestion
Digestion
Absorption
Compaction
Excretion
What is chemical digestion
Hydrolysis reaction —> breaks dietary macromolecules into individual monomers
What are the enzymes found in chemical reaction
Polysaccharides (glucose)
Proteins (amino acids)
Lipids (monoglyceride/fatty acids)
Nucleic acids—-> nucleotides
What are the accesory organs
Teeth,tongue,salivary glands,liver,gallbladder, pancreas
What is in the digestive tract
Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus
Enteric nervous control
Esophagus, stomach, intestines
Regulates digestive tract mobility
Secretion
Blood flow
Nerve networks from enteric nervous control
Submucosa plexus- controls grandular secretion
Controls movement of muscularis mucosae
Myenteric plexus- parasympathetic (ganglia and nerve fiber)
Controls paristalsis
Peritoneum
Serious membrane that lines peritoneal cavity of abdomen
Most digestion occurs within this
NOT IN PERITONEUM CAVITY—> DUODENUM, PANCREAS, PARTS OF LARGE INTESTINE
HAS TWO LAYERS
DORSAL - suspends Gi tract and forms serosa of STOMACH AND INTESTINES
VENTRAL- forms lesser and greater omentum
Lacy layer of connective tissue and contains lymph nodes, lymphatic vessels, blood vessels
Appearance of this because of many holes pf gaps in the membrane and irregular distribution of fatty tissue
Regulation of digestive tract
Motility and secretion of digestive tract are controlled by
Neural
Hormonal- secreted into blood stream (stimulate distant parts of digestive tract)
Hormones created—> gastric and secretion
Paracrine secretions- chemical messengers diffuse through tissue fluid
Stimulate nearby cells
Secretions —-> histamine and prostaglandins
Teeth: Dentition
Deciduous : baby teeth (20) by age 2
Adult: (32) 16 in mandible and maxilla
Incisors, canines, premolars, molars
Tooth and gum disease
Humans mouth : 700 species of microorganisms
Plaque: sticky residue —> bacteria or sugars
Root canal therapy —-> if cavity reaches pulp
Gingivitis : inflammation of gums
Periodontal disease: destruction of supporting bone around teeth (may result in tooth loss)
Mastication or chewing (step 1)
Breaks food into smaller pieces to be swallowed
Contact of food with sensory receptors—> triggers chewing reflex
Functions of saliva
Moistens the mouth
Begins starch and fat digestion
Cleanse teeth
Inhibit bacteria
Moistens food and binds it together into bolus
Hypotonic solution
99.5% water and solutes
Hypotonic solution: amylase
Begins starch digestion
Hypotonic solution: Lingual lipase
Digest fat after reaches the stomach (activated by stomach acid)
Hypotonic solution: Mucous
Binds and lubricates mass of food and aids in swallowing
Hypotonic solution: Lysozyme
Enzyme that kills bacteria
Hypotonic solution: Immunoglobulin
Inhibits bacteria growth
PH of saliva/salivary glands
6.8 —> 7.0
Extrinsic glands
3 types:
Parotid gland: earlobe
Submandibular gland:
Sublingual gland: floor of mouth
2 cells
Mucous cell: secrete mucous
Serous cell —> secrete thin fluid (rich in enzymes) amylase and electrolytes
Salivation
Salivary glands secrete: 1 —-> 1.5 L of saliva per day
Salivary amylase —> beings to digest starch (food is chewed)
Binds food particles into soft —> slippery —> blous
The esophagus:
Mucosa: nonkaretinized stratified squamous epithelium
Submucosa: esophageal glands
Muscularis external: skeletal muscle in
Upper skeletal —-> smooth in bottom (shift)
Voluntary ———-> involuntary of swallowing
Swallowing (deglutition)
Action involving 22 muscles
Mouth —> pharynx —> esophagus
Medulla oblongata coordinates swallowing
Stages in swallowing
Oral (buccal) phase :voluntary control
Pharyngeal: involuntary control
Esophageal: involuntary wave of muscular contraction and pushes bolus ahead of it
Oral (Buccal) phase
Tongue forms food bolus and pushes into laryngopharynx
Pharyngeal phase
Palate —> tongue —> vocal cords —> epiglottis
Block ORAL — > NASAL —> airway
Pharyngeal constrictors push bolus into esophagus
Esophageal phase
“Peristalsis” drive bolus downward
Esophageal sphincter admits it into the stomach
Stomach intro
Mechanically breaks up food —-> liquifies —> chemical digestion of protein and fat
CHYME = liquified portion of food
Absorption = chyme passed on to small intestines.
Innervation of stomach
Parasympathetic —> fibers from vagus nerve
Sympathetic —> fibers from celiac ganglia
Stomach + intestines = drainage —> enters hepatic portal circulation —> filtered through liver
Cells of gastric glands: Regenerative (stem) cells
supply of new cells to replace cells that die
Cells of Gastric glands: Parietal cells
Secrete HCI acid and intrinsic factor
Cells of gastric glands: Cheif cells
Secrete pepsinogen in infancy (protein)
Cells of gastric glands: Enteroendocrine cells
Secrete hormones and paracrine messengers that regulate digestion
G cell produce Gastrin
Intrinsic factor (parietal cells)
Essential for B12 absorption by small intestine
Necessary for hemoglobin synthesis (not enough= anemia) RBC production
Pepsin (chief cells)
Protein digestion —> Secreted by pepsinogen
HCI converts pepsinogen to pepsin (removes its amino acids)
Gastric lipase (chief ells)
Gastric / lingual lipase play minor role in digestion dietary fats
Chemical messengers( g cells)
Many produced by enteroendocrine cells of gastric and pyloric glands
Protection of stomach
Protected 3 ways BC HARSH ACIDIC —> ENZYMATIC ENVIRONMENT CREATED
Mucous coat
Tight junction: between epithelial cells prevent gastric juice from seeping between them
Epithelial cell replacement : live 3-6 days
Sloughed off into chyme and digested with food
Replaced rapidly B cell division in gastric pits
Bile duct system
Right and Left hepatic Ducts
-collect bile form all bile ducts
Unit a common hepatic duct—> leaves liver
BILE flow —> common bile duct or cystic duct (leads to gallbladder)
Bile
Yellow-green fluid containing minerals, cholesterol, neutral fats, phospholipids, bile pigments, bile acids
Pancreas
Retroperitoneal gland (posterior to greater curvature of stomach)
Small intestine : Duodenum
“Mixing bowl” receives chyme from stomach and digestive secretion. From pancreas and liver
Neutralizes stomach acids, emulsifies fats, pepsin inactivated by pH increase, pancreatic enzymes
Small intestine : Jejunum
Chemical digestion and nutrient absorption occur here
Small intestine: Ileum
Ends ileocecal junction
Circulation
Small intestine receives nearly blood supply from Superior mesenteric artery
Superior mesenteric vein
Splenic vein and flows into hepatic portal system
segmentation
Most common movement (mix and churn)
Peristaltic (moves chyme towards large intestines/colon)
Carbohydrates
Most dietary carbohydrate : starch
Digestion begins in mouth —> salivary amylase —> hydrolyze starch —> oligosaccharides
Amylase —> pH of 6.8 -7 of oral
50% of dietary starch digested before reaching small intestine
Pancreatic amylase —> resumes starch digestion in intestine
Starch -> oligosaccharide -> Maltose Glucose -> absorbed by small intestines
Proteins
Digest proteins -> proteases
Absent in saliva BUTTTT work in stomach
Stomach (pepsin)
Small intestine (action of pancreatic enzyme)
Lipids
Fats emulsified than digested by lipase enzymes
Nucleic acids, vitamins, minerals
Nucleases —> hydrolyze DNA and RNA into nucleotides
Vitamins —> are absorbed unchanged
Minerals —> electrolytes are absorbed all along the small intestine
Water
Water absorbed by osmosis —> absorption of salts and organic nutrients
Protein digestion and absorption
Pepsinogen is converted to pepsin BYYYYY HCI —> chemical digestion protein
Male/female combine their eggs
gametes (sex cells) = zygote (fertilized egg)
What does the male reproductive system serves as?
Produce sperm and introduce them into female body
What does female reproductive system serves as?
Produces eggs, receives sperm, provides for gametes union harbors fetus and nourishes offspring.
Primary sex organs
Tetes and ovaries (produce gametes)
Secondary sex organs
Organs other than gonads that are necessary for reproduction
What is the SRY gene
Codes for protein, testes-determining factor that causes development of testes.
Secrete testosterone 8-9 weeks
Testes secrete mullerian-inhibiting factor causing degeneration of the paramesonephric ducts
Embryonic development (3 structures)
External genitals of both sexes begin
Genital tubercle-> head of gland of penis or clitoris
Pair of urogenital folds-> enclose urethra of male helping to form penis or labia minora
Pair of labioscrotal folds-> scrotum or labia majora
Spermatic cord has
Bundle of fibrous connective tissue
HAS: testicular (blood vessels) nerves, lymphatic vessels and ductus deferens
Why and where are the testes located
In scrotum
Cooler environment
CANNOT PRODUCE SPERM AT CORE BODY TEMP 37C*
Needs to be 35C*
Growth of sex organs
Penis, testes, ducts, glands
What does testosterone maintain during adulthood
Libido , spermatogenesis, reproductive tract
When there isn’t enough testosterone what happens
Raise in FSH and LH producing male (menopause)
Erectile dysfunction
Inability to produce or maintain erectile sufficient for intercourse
Process of meiosis
Reduces chromosomes # anddddd
Producing 4 daughter cells that will become sperm
What’s the difference between Mitosis and Meiosis
Mitosis: two genetically identical daughter cells
Meiosis: produces gametes
Keeps chromosome constant (generation->generation)
2 cell divisions
Meiosis 1-> sperates homologous chromosome pairs into 2 haploid cells
Meiosis 2 -> separates duplicated sister chromatids into 4 haploid cells
What does spermatogonia do
Produce 2 kinds of daughter cells
Type A- tubule wall as a stem cell
Type B- produces sperm (primary sperm)
what makes up semen fluid
60% seminal vesicle fluid
30% prostatic fluid
10% sperm and spermatic duct secretions
Sperm count
50-120 million/mL
Lower than 20/25 million/ mL = infertility
