Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PSIO 202 > PSIO Exam 4 > Flashcards

PSIO Exam 4 Flashcards

1
Q

Smooth Muscle

A
  • modulates luminal pressure/tension

- tissue is present in sheets, bundles or sheaths around tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Innervation and Stimulation of Smooth Muscle

A
  • primarily under control of ANS “involuntary”
  • diffuse branching of nerve fibers
  • transmitters include ACh and NE
  • membrane potential ~ -50 to -60mV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Smooth Muscle Cells type categorized based on excitation

A
  • single/unitary (visceral)

- multi-unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Unitary Smooth Muscle Cells

A
  • walls of digestive tract, gall bladder, urinary bladder
  • may not have direct contact with any motor neuron
  • AUTORHYTHMIC. Adjacent cells connect via gap junctions and transmit AP from one fiber to another
  • cell membranes adhere to one another: transmission of force
  • slow synchronized “graded” contraction
  • entire sheet of muscle contracts as a “functional syncytium”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Diffuse Junctions

A

general area of smooth muscle fiber where numerous viscosities are located and release neurotransmitters into

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Structure of Smooth Muscle Cells

A
  • sarcoplasmic reticulum is poorly developed relative to skeletal muscle
  • thick filaments of SM have actin-gripping heads along their entire length
  • thick and thin filaments are arranged diagonally within the cell contraction results in twisting motion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Special Features of SM

A
  • capable of sustained contraction without fatigue and at little energy cost
  • maintains a low level of tension or tone even in the absence of action potentials
  • stress relaxation response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

SM Stretch Relaxation Response

A
  • stretch causes initial increase in tension
  • tension decreases within 1-2 minutes
  • allows SM to change length but maintain ability to contract (important for storage organs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Length-Tension Relationship in SM

A
  • smooth muscles operate over a wider range of resting lengths
  • generally broader length-tension relationship in smooth muscle compared to skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Parts of Stomach

A
  • cardia
  • fundus
  • body
  • pylorus
  • pyloric sphincter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Stomach Anatomy

A
  • stomach filling triggers secretions and motility

- stomach empties slowly into the duodenum as small squirts of chyme leave through the pyloric sphincter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Parietal Cell Function

A

secrete HCl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mechanical Digestion in Stomach

A
  • gentle mixing waves occur in the stomach to mix the blouse of food with gastric juice (enzyme, acid, water) and turn it into chyme (a thin liquid)
  • more vigorous waves traveling from the body of stomach to the pyloric region move the chyme along
  • intense waves near the pylorus lead to opening of the pyloric sphincter- squirting 1-2 teaspoons into the duodenum with each wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Chemical Digestion in Stomach

A
  • protein digestion begins in the stomach
  • fat digestion continues
  • HCl kills microbes in food
  • mucous cells secret mucus to protect the stomach walls from being digested
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Protein digestion in stomach

A
  • HCl denatures (unfolds) protein molecules

- HCl activates pepsinogen into pepsin- an enzyme that breaks peptide bonds between certain amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Fat digestion continues

A

gastric lipase splits the triglycerides in milk fat, although this is most effective at pH 5-6 (infant stomach)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Absorption of Nutrients by the Stomach

A
  • water
  • electrolytes
  • some drugs (aspirin) and alcohol
  • fat content in the stomach slows the passage of alcohol to the intestine, where absorption is more rapid
  • alcohol is absorbed more slowly if taken with a meal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Regulation of Stomach Function: Neural Influences

A
  • stretch receptors & chemoreceptors (pH) signal bolus entry, and this leads to an increase in parasympathetic nerve impulses to effectors in the stomach
  • vigorous peristalsis and gastric gland secretions result
  • chyme periodically released into the duodenum until return to homeostasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Regulation of Stomach Function: Endocrine (hormonal) influences

A

distention and presence of food in stomach cause G cells to secrete gastrin into the bloodstream; gastrin increases gastric gland secretions and motility, and cause pyloric sphincter relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Anatomy of the Small Intestine

A
  • 3m (10 feet) in length
  • 2.5 cm (1.0 in) in diameter
  • large surface area
  • site of most digestion and absorption
  • divided into sections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Sections of Small Intestine

A
  1. duodenum 25 cm (10 in) starts at pyloric sphincter
  2. jejunum 1 m (3 ft)
  3. ileum 2m (6 ft) ends at ileocecal sphincter valve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Total length of small intestine in cadavers

A

6.5 m (21 ft) due to loss of smooth muscle tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Functions of Villi and Microvilli

A
  • increase surface area for absorption
  • brush border enzymes found on the surfaces of microvilli participate in chemical breakdown of carbohydrates, proteins, and nucleosides
  • cell division within intestinal glans produces new cells that move up to replace old cells that have been lost
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Brush border enzymes on microvilli

A
  • pancreatic juice is present in the lumen with chyme, and contains amylase, proteases, lipase and nucleases
  • no brush border lipase or nucleases present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Pancreatic Juice (~2L produced per day)

A

clear colorless liquid (pH of 7.1 to 8.2) consisting of:

  • water
  • salts
  • sodium bicarbonate
  • several enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Enzymes secreted by the pancreas

A
  1. pancreatic amylase
  2. trypsin
  3. chymotrypsin
  4. carboxypeptidase
  5. elastase
  6. pancreatic lipase
  7. ribonuclease
  8. deoxyribonuclease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Proteases

A

secreted as inactive precursors (like pepsinogen in the stomach)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Enteropeptidase (on brush-border cells)

A

activates trypsinogen to trypsin, trypsin then activates chymotrypsinogen, procaboxypeptidase, and proleasease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Digestion of carbohydrates

A
  • mouth: salivary amylase
  • stomach: mechanical only
  • pancreas: pancreatic amylase in pancreatic juice
  • small intestine: brush border enzymes maltase, sucrase, and lactase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Small intestine brush border enzymes: carbohydrates

A
  • act on disaccarides (maltose, sucrose, and lactose)

- produce monosaccharides (fructose, glucose, and galactose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Lactose Intolerance

A

those without lactase will have bacteria ferment lactose, and the result will be gas and diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Absorption of Monosaccharides

A
  1. Absorption into epithelial cells
    - glucose & galactose: sodium symporter (secondary active transport)
    - fructose: facilitated diffusion
  2. Movement out of epithelial cell into bloodstream
    - by facilitated diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Digestion of Proteins

A
  • mouth: mechanical only
  • stomach: Hal denatures or unfolds proteins, and pepsin breaks proteins into smaller polypeptides -smaller chains of amino acids
  • pancreas: pancreatic enzymes (proteases) in pancreatic juice continue to split peptide bonds between amino acids
  • small intestine: brush border enzymes amino peptidase and dipeptidase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Small intestine brush border enzymes: proteins

A
  • split off amino acids at the amino end of polypeptides (amino peptidase)
  • split apart two-amino acid chains (dipeptidase)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Absorption of Amino Acids & Dipeptides

A
  1. Absorption into epithelial cells of duodenum and jejunum
    - active transport with Na+ of H+ ions (symporters using secondary active transport)
  2. Movement out of epithelial cell into blood
    - by facilitated diffusion
36
Q

Digestion of Lipids

A

-begins in the mouth thanks to lingual lipase in saliva
-continues in the stomach thanks to gastric lipase
(gastric lipase is especially important for digestion in infant)
-pacreas: pancreatic lipase in pancreatic juice continues to split triglycerides into fatty acids and monoglycerides
-liver: bile emulsifies lipids to form tiny micelles
-there is no digestion of lipids by the small intestine itself (no lipase enzymes in the membranes of brush border cells)

37
Q

Absorption of Lipids

A
  1. short-chain fatty acids are absorbed by simple diffusion
  2. long-chain fatty acids and monoglycerides (products of lipases) are sequestered within tiny micelles after emulsification by bile; will also enter cells by simple diffusion, leaving bile salts behind
    - bile salts are also reabsorbed and later recycled (into bile) by the liver
    - fat-soluble vitamins (A, K, D3, E) are able to enter cells with lipids.
  3. inside epithelial cells fats are rebuilt and coated with protein to form chylomicrons
  4. chylomicrons leave intestinal cells by exocytosis into interstitial fluid where they can only enter lacteals (too big for capillaries)
    - travel in lymphatic system to reach subclavian veins
    - removed from the blood by the liver and fat tissue
38
Q

Absorption of Electrolytes

A
  1. source of electrolytes (GI secretions, ingested foods and liquids)
  2. enter epithelial cells by diffusion and secondary active transport
  3. Intestinal Ca2+ absorption requires vitamin D and parathyroid hormone.
39
Q

Active transport by electrolytes

A
  • sodium and potassium move by active transport
  • chloride, iodide and nitrate follow passively
  • iron, magnesium, and phosphate ions use active transport
40
Q

Absorption of vitamins

A
  1. fat soluble vitamins (A, K, D3, E)
    - travel in micelles and are absorbed by simple diffusion with lipids
  2. water-soluble vitamins
    - absorbed by diffusion
  3. vitamin B12 must combine with intrinsic factor from the stomach parietal cells before it is transported into the cells of the ileum
    - absorbed by receptor mediated endocytosis
41
Q

Absorption of Water

A
  • 9L fluid enters the GI tract per day
  • small intestine absorbs 8L
  • large intestine absorbs 90% of the last liter
  • absorption of its accomplished by osmosis- through cell membranes into cells and then from the cells into the capillaries inside the intestinal villi
42
Q

The Manifold Functions of the Liver

A
  • metabolism of carbohydrates, proteins, and lipids
  • detoxifies the blood by removing or altering drugs and hormones (thyroid and estrogen)
  • removes bilirubin (waste product of red blood cell breakdown)
  • releases bile salts to help digestion by emulsification of lipids
  • stores fat-soluble vitamins (A, D3, E, K)
  • stores iron, copper and vitamin B12
  • phagocytosis of worn out blood cells and bacteria
  • plays a role in the vitamin D activation pathway
43
Q

Blood Flow through the Liver

A

blood from the hepatic arteries and hepatic portal vein mixes, and the mixed blood flows through the sinusoidal capillaries of the liver before returning to venous circulation

44
Q

Liver’s Functional Unit: The Liver Lobule

A
  • hepatocytes are the primary cells of the liver, doing most of the work
  • hepatocytes arranged in grids in lobules
  • spaces between hepatocytes are either blood-filled sinusoid or bile canaliculi
  • kupffer cells phagocytize microbes and foreign matter
45
Q

Pathway of Bile Secretion

A
  • bile canaliculi join to form bile ducts which form hepatic ducts
  • L & R hepatic ducts form the common hepatic duct
  • the cystic duct from gallbladder and the common hepatic duct join to form common bile duct
  • common bile duct & main pancreatic duct empty into duodenum
46
Q

Carbohydrate Metabolism Liver Function

A
  • turn amino acids into glucose (gluconeogenesis)
  • turn triglycerides into glucose (gluconeogensis)
  • turn excess glucose into glycogen & store in the liver (glycogenesis)
  • turn glycogen back into glucose as needed (glycogenolysis)
47
Q

Lipid Metabolism Liver Function

A
  • synthesize cholesterol
  • synthesize lipoproteins such as HDL and LDL, which are used to transport fatty acids and cholesterol in the bloodstream
  • stores some fat
  • breaks down some fatty acids
48
Q

Protein Metabolism Liver Function

A
  • deamination
  • convert resulting toxic ammonia (NH3) into urea for excretion by the kidney
  • transamination
  • synthesizes plasma proteins utilized in the clotting mechanism and immune system
49
Q

Deamination

A

removes -NH2 (amine group) from amino acids so we can use what is left as an energy force

50
Q

Transamination

A

converts one amino acid into another

51
Q

Functions of Large Intestine

A
  • smooth muscle: mechanical digestion
  • peristaltic waves (3 to 12 contractions/minute)
  • haustral churning
  • bacteria ferment undigested carbohydrates into carbon dioxide and methane gas, and undigested proteins into simpler substances
  • gastroilial reflex, gastrocolic reflex, defecation reflex
52
Q

Haustral Churning

A

relaxed pouches are filled from below by muscular contractions; when full, they contract and move contents to next pouch

53
Q

Gastroilial reflex

A

when stomach is full, gastrin hormone relaxes ileocecal sphincter so small intestine will empty into large intestine

54
Q

Gastrocolic reflex

A

when stomach fills, a strong peristaltic wave moves contents of transversals colon into rectum

55
Q

Defacation reflex general

A

when rectum fills, input to sacral spinal cord return commands to expel feces

56
Q

Defacation reflex detailed

A
  1. gastrocolic reflex moves feces into rectum
  2. stretch receptors signal sacral spinal cord
  3. parasympathetic nerves contract muscles of rectum and relax internal sphincter
    (external anal sphincter is voluntarily controlled)
57
Q

Regulation of digestion

A
  1. cephalic phase
  2. gastric phase
  3. intestinal phase
58
Q

Cephalic phase (anticipation)

A
  • prepare the mouth and stomach for food
  • cerebral cortex: sight, smell, taste, and thoughts of food stimulate the parasympathetic nervous system to stimulate salivation (facial and glossopharyngeal) and gastric glands to secrete gastric juice (vagus)
59
Q

Gastric phase (breakdown of material)

A
  • neural influences

- endocrine influences

60
Q

Neural influences over stomach activity

A
  • stretch receptors and chemoreceptors (pH) signal bolus entry
  • vigorous peristalsis and gastric gland secretions
  • chyme periodically released into the duodenum
61
Q

Endocrine influences over stomach activity

A

distention and presence of food in stomach cause G cells to secrete gastrin into the bloodstream; gastrin increases gastric gland secretions and motility, and causes pyloric sphincter relaxation

62
Q

Gastric emptying increased as bolus of food enters stomach

A
  • distention of the stomach and presence of undigested contents increase the secretion of gastrin hormone and vagal nerve impulses
  • this stimulates contraction of the lower esophageal sphincter and the stomach, as well as relaxation of the pyloric sphincter for emptying
63
Q

Intestinal phase (controlled release of chyme)

A

entry of chyme into duodenum slows gastric activity and increases intestinal activity

64
Q

Neural influences over intestinal activity

A

distention of the duodenum and chemical contents of the chyme activate sympathetic nerves, which slow gastric activity (enterogastric reflex)

65
Q

Endocrine influences over intestinal activity

A

distention of duodenum and contents of chyme trigger hormonal release from enteroendocrine cells in the duodenum

  • secretin hormone decreases stomach secretions
  • cholecystokinin (CCK) decreases stomach emptying
66
Q

Enterogastric reflex: regulates the amount of chyme released into the duodenum

A
  • initiated by distention of duodenum and contents of the chyme
  • sensory impulses sent to the medulla inhibit parasympathetic stimulation of the stomach
  • cause CCK and secretin release from the duodenum and stimulate sympathetic impulses, both of which inhibit gastric emptying
67
Q

Regulation of pancreatic secretions by enteroendocrine cells

A
  1. secretin: acidity in intestine causes increased sodium bicarbonate release
  2. CCK (cholecystokinin): fats and proteins cause increased digestive enzyme release
68
Q

Regulation of bile secretion by enteroendocrine cells

A
  1. parasympathetic impulses along vagus nerves stimulate bile production by liver
  2. fatty acids and amino acids in chyme entering the duodenum stimulate secretion of CCK into blood. acidic chyme entering duodenum stimulates secretion of secretin into blood
  3. CCK causes contraction of gallbladder
  4. secretin enhances flow of bile rich in HCO3- from liver
69
Q

Catabolic reaction

A

breaks down complex organic compounds, providing energy

70
Q

Anabolic reaction

A

synthesize complex molecules from small molecules, requiring energy

71
Q

ATP’s central role in metabolism

A
  • each cell has 1 billion ATP molecules (equals ~2 seconds of max contraction for skeletal muscle); rapid ADP-ATP turnover
  • over half of the energy released from ATP is lost as heat
72
Q

Energy Transfer

A
  • energy is found in the bonds between atoms
  • oxidation is a decrease in the energy content of a molecule: electrons lost, plus H+
  • reduction is an increase in the energy content of a molecule: electrons gained, plus H+
  • sometimes an intermediate molecule is involved in electron transfer: coenzyme (NAD+ and FADH)
73
Q

4 Steps of Glucose Catabolism

A
  1. glycolysis
  2. formation of acetyl coenzyme A
  3. Krebs cycle
  4. electron transport chain (ETC)
74
Q

Transport of Lipids by Lipoproteins

A
  • most lipids are non polar and must be combined with protein to be transported in blood
  • lipoproteins are spheres containing hundreds of molecules
  • lipoproteins are categorized by function and density
  • 4 major classes of lipoproteins
75
Q

Classes of Lipoproteins

A
  • chylomicrons
  • very low-density (VLDLs)
  • low-density (LDLs)
  • high-density (HDLs)
76
Q

Chylomicrons

A
  • 2% protein, 85% TG

- form in intestinal epithelial cells to transport dietary fats to adipose cells

77
Q

VLDLS (ver low-density)

A
  • 10% protein, 50% TG

- form in hepatocytes to transport triglycerides to adipose cells

78
Q

LDLs (low-density)

A
  • 25% protein, 50% Cholesterol
  • bad cholesterol
  • carry blood cholesterol to body cells
79
Q

HDLs (high-density)

A
  • 40% protein, 20% Cholesterol
  • good cholesterol
  • carry cholesterol from cells to liver for elimination
80
Q

Fate of Lipids

A
  • oxidized to produce ATP
  • excess stored in adipose tissue or liver
  • synthesize structural or other important molecules
81
Q

Other important lipid molecules

A
  • phospholipids of plasma membrane
  • lipoproteins that transport cholesterol
  • thromboplastin for blood clotting
  • myelin sheaths to speed up nerve conduction
  • cholesterol used synthesize bile salts and steroid hormones
82
Q

Thromboplastin

A

phospholipids and tissue factor are needed to activate the extrinsic pathway of blood clotting

83
Q

Lipolysis

A

triglycerides are broken down into glycerol and fatty acids within liver or adipose cells in the presence of epinephrine, norepinephrine, cortisol

  • beta oxidation
  • ketogenesis
84
Q

Lipogenesis

A

triglycerides are synthesized from amino acids or glucose within liver or adipose cells in the presence of insulin

85
Q

Beta oxidation

A

fatty acids undergo beta oxidation in mitochondria to produce Acetyl CoA and lots of ATP

86
Q

Ketogenesis

A

occurs in liver cells; ketone bodies are used by heart muscle and kidney cortex for ATP production

87
Q

Fuel sources for lipogenesis

A
  1. amino acids, glycolysis metabolites, and ketone bodies for fatty acid production from Acetyl-CoA
  2. glycolysis metabolites for glycerol production

PSIO 202 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions