Human Structure & Function Ii - Final Exam

Front 1

The Gastroenteric Reflex

Back 1

-Stimulates motility and secretion along entire small intestine
-N.B. the enterogastric reflex inhibits gastric motility and secretion!

Front 2

The Gastroileal Reflex

Back 2

-Triggers relaxation of ileocecal valve/sphincter
-Allows materials to pass from small intestine into large intestine

Front 3

Liver

Back 3

-Is wrapped in tough fibrous capsule
-Is covered by visceral peritoneum
-Is divided into lobes: Left, Right, Caudate, Quadrate

Front 4

Liver (metabolic activities)

Back 4

-Carbohydrate metabolism
-Lipid metabolism
-Amino acid metabolism
-Waste product removal
-Removal or storage of toxins
-Vitamin storage
-Mineral storage
-Drug inactivation
*Synthesis and secretion of bile

Front 5

Liver (hematological regulation)

Back 5

- Phagocytosis and antigen
presentation
- Synthesis of plasma proteins
- Removal of circulating hormones
- Removal of antibodies

Front 6

Portal Triad

Back 6

-branch of hepatic artery
-branch of hepatic portal vein
-small bile duct

Oxygenated Blood from Hepatic Artery & Nutrient Rich Deoxygenated blood from Portal Vein --> Liver Sinusoid --> Central Vein --> Hepatic Vein --> Inferior Vena Cava --> Right Atrium of Heart

Front 7

Bile

Back 7

-One quart of bile/day is secreted by the liver
-yellow-green in color & pH 7.6 to 8.6
-Components
-water & cholesterol
-bile salts = Na & K salts of bile acids
-bile pigments (bilirubin) from hemoglobin molecule
1)globin = a reuseable protein
2)heme = broken down into iron and bilirubin

Front 8

Emulsification of Fat

Back 8

Large lipid droplet --> (bile & mixing) --> emulsified fat (miscelles) --> (pancreatic lipases) --> fatty acids & 2-monoglycerides

Front 9

Enterohepatic Recirculation of Bile

Back 9

95% of bile salts transferred in blood through hepatic portal vein & back into liver for redistribution/reuse

Front 10

Gall Bladder & Biliary System

Back 10

Right & Left Hepatic Duct --> Common Hepatic Duct from Liver --> Cystic Duct from Gallbladder enters --> Common Bile Duct --> Pancreatic Duct from Pancreas enters --> Duodenum

Front 11

Regulation of Bile Secretion

Back 11

1) Increase in Acid --> Increase in Plasmin Secretion --> Increase in Bile secretion from liver --> Increase in Bile in Duodenum --> Neutralization of Fat

2) Increase in Protein Digestion Products & Fat --> Increase in Plasma CCK --> Gallbladder (contraction) & Sphincter of Oddi (relaxation) --> Increase in Bile in Duodenum --> Emulsification of Fats

Front 12

Pancreas

Back 12

-Has both exocrine (acini) and endocrine (Islets of Langerhans) portions
-Exocrine portion produces pancreatic juice
1) Rich in bicarbonate
2) Enzymes: Pancreatic amylase and lipases; Proteases

Front 13

Release of Pancreatic Secretions

Back 13

-CCK stimulates acinar cells to secrete enzymes
-Secretin stimulates duct cells to secrete bicarbonate
-Negative feedback loop

Front 14

Review Mechanisms for Moving Nutrients through Epithelium

Back 14

GI slide 83

Front 15

Vitamin Absorption

Back 15

-Fat-soluble vitamins (A, D, E, and K)
--> Absorbed with lipids
--> Dissolve in lipid droplets, micelles, chylomicrons
-Water-soluble vitamins
--> Require special transport proteins
-Vitamin B12
--> Absorbed only when bound to intrinsic factor

Front 16

Vitamins Produced in Large Intestine

Back 16

1) Vitamin K (fat soluble) --> Required by liver for synthesizing four clotting factors, including prothrombin
2) Biotin (water soluble) --> Important in glucose metabolism
3) Pantothenic acid: B5 (water soluble) --> Required in manufacture of steroid hormones and some neurotransmitters

Front 17

Defecation Reflex

Back 17

-Short Reflexes --> intramural plexuses
-Long Reflrexes --> from spinal cord & higher brain centers
-triggered by distension of walls
-positive feedback loop involving peristalsis
-both sphincters open, inhalation, voluntary holding of breath --> high pressure in abdominal cavity --> defecation

-Review GI slide 98

Front 18

Paneth Cells

Back 18

-provide host defense against microbes in the small intestine. When exposed to bacteria or bacterial antigens, Paneth cells secrete a number of antimicrobial molecules into the lumen of the crypt, thereby contributing to maintenance of the gastrointestinal barrier. 
-The principal defense molecules secreted by Paneth cells are alpha-defensins, also known as cryptdins
-Paneth cells secrete lysozyme and phospholipase A2, both of which have clear antimicrobial activity. This battery of secretory molecules gives Paneth cells a potent arsenal against a broad spectrum of agents, including bacteria, fungi and even some enveloped viruses.

Front 19

Functions of Urinary System

Back 19

1) Homeostatic regulation of blood plasma volume and content
2) Excretion and elimination

-regulated neurally & hormonally (hormones are major controllers)

Front 20

Homeostatic Functions of Urinary System

Back 20

1)Regulates blood volume and blood pressure --> By adjusting volume of water lost in urine & Releasing erythropoietin and renin
2) Regulates plasma ion concentrations --> Sodium, potassium, and chloride ions (by controlling quantities lost in urine) & Calcium ion levels (through synthesis of calcitriol)
3) Helps stabilize blood pH --> By controlling loss of hydrogen ions and bicarbonate ions in urine
4) Conserves valuable nutrients --> By preventing excretion while excreting organic waste products
6) Assists liver in detoxifying poisons

Front 21

Typical Adult Kidney

Back 21

-All urinary components are retroperitoneal
-Is about 10 x 5.5 x 3 cm thick (4 x 2.2 x 1.2 in.)
-Weighs about 150 g (5.25 oz)
-hilum faces posteriorly & medially

Front 22

Kidneys --> 1
Ureter --> 2
Bladder --> 3
Urethra --> 4

Back 22

1) produces urine
2) transports urine to bladder through peristalsis
3) stores urine until it can be eliminated
4) transports urine to exterior (in males, transports semen as well)

Front 23

Kidney Characteristics

Back 23

-left kidney lies superior to right kidney
-superior surface capped by adrenal galnd (aka suprarenal gland)
-kidneys protected & stabilized by
1) fibrous capsule --> thin & delicate (outer)
2) perinephric fat capsule --> mostly white adipose (may be some brown adipose)
3) renal fascia (inner)

Front 24

Floating Kidneys

Back 24

-associated with starvation --> fat which typically stabilizes kidneys is being used up

Front 25

Renal Sinus

Back 25

-hollow portion in kidney where urine collects before entering ureter

Front 26

Kidney (anatomy)

Back 26

-superficial cortex
-deep medulla
-renal columns --> divide kidney into renal pyramids & serve as a passageway for blood vessels
-renal pyramids (aka renal lobes) --> about 12 pyramids per kidney
-renal papilla --> tip of pyramid that leads into renal sinus
-minor & major calices
-about 1,000,000 nephrons in each kidney

Front 27

Renal Vasculature

Back 27

abdominal aorta --> renal artery --> segmental a. --> interlobar a. --> arcuate a. --> interlobular a. --> afferent arteriorles --> glomerulus --> efferent arteriole --> peritubular capillaries --> interlobular vein --> arcuate veins --> interlobar veins --> renal vein

Front 28

Afferent Arterioles _______ than Efferent Arterioles --> ______

Back 28

Afferent arterioles are larger than efferent arterioles --> high pressure in glomerulus --> controls glomerular filtration

Front 29

Nephron

Back 29

-vascular component & tubular component

Front 30

Glomerulus & Bowman's Capsule

Back 30

-Glomerulus (capillaries) interact w/ Bowman's Capsule (tubular portion)
-fluid enters space between 2 sides of Bowman's Capsule
-inner layer of BC (visceral layer) comes into direct contact with capillaries
-parietal layer, Bowman's space, visceral layer

Front 31

Renal Corpuscle

Back 31

-glomerulus & Bowman's Capsule

Front 32

Podocytes

Back 32

-cover capillaries of glomerulus
-have "feet"

Front 33

Filtration Slits

Back 33

-space between podocytes
-surface through which blood must pass to get into Bowman's space
-restricts movement of cells, proteins, & large molecules
-allows water & small molecules to pass
-one way movement from plasma --> forming urine (due to starling forces)

Front 34

Juxtamedullary Nephron

Back 34

-involved in formation of concentrated urine

Front 35

Urine

Back 35

-considered urine once it reaches the minor calyx at the papilla

Front 36

Vasa Recta

Back 36

-peritubular capillaries that follow the loop of Henle (critical to function) in the Juxtamedullary Nephrons

Front 37

Proximal Convoluted Tubule

Back 37

-simple cuboidal epithelium w/ brush border
-have mitochondria in walls to support active transport

Front 38

3 Kinds of Exchange (Urinary System)

Back 38

1) Glomerular Filtration
2) Tubular Secretion
3) Tubular Reabsorption

Front 39

Glomerular Filtration

Back 39

-occurs in renal corpuscle
-least regulated (non-specific)
-astronomical volume of water exchange

Front 40

Tubular Secretion

Back 40

-additional blood elements added to filtrate
-secretion into tubule = unidirectional

Front 41

Tubular Reabsorption

Back 41

-elements reabsorbed back into blood

Front 42

Tubular Secretion & Reabsorption

Back 42

-hormonally regulated
-pretty specific regulation

Front 43

Juxtaglomerular Apparatus

Back 43

-senses blood pressure & stimulates change
-Macula Densa
-Juxtaglomerulat Cells --> secrete renin

Front 44

Renin-Angiotensin-Aldosterone System

Back 44

-short term regulation of blood pressure

Front 45

Long Term Regulation of Blood Pressure

Back 45

-controlled by adjusting blood volume

Front 46

Minor Calyx --> Bladder

Back 46

-all have transitional epithelium

Front 47

Bladder

Back 47

-transitional epithelium
-stores urine
-Female --> anterior & inferior to uterus; urethra = short & straight
-Male --> longer urethra; shared between urinary & reproductive systems

Front 48

Glomerular Filtration

Back 48

-non-specific
-takes all elements out of blood & later adds them back selectively

Front 49

Starling Forces

Back 49

-Glomerulus Capillary Hydrostatic Pressure
-Bowman's Capsule Hydrostatic Pressure
-Glomerular Oncotic Pressure
-Bowman's Capsule Oncotic Pressure

Glomerular Filtration Pressure = (Pgc + Obc) - (Pbc + Ogc) =(60 + 0) - (15 + 29) = 16 mm Hg into Bowman's Capsule

Front 50

Filtration Fraction

Back 50

-625 mL plasma enter kidneys per minute
-125 mL filtered into Bowman's Capsule
-125/625 = 20% = filtration fraction
-takes 5 cycles of blood (~ 5 mins) to completely filter blood

Front 51

Glomerular Filtration Rate

Back 51

~125 mL/min = 180 L/day
(compared to systemic caps --> filt. press. = 2 mm Hg; filt. rate = 3 liters/day)
-only 1.5 liters of urine excreted/day (<1%)
-99% of filtered fluid is reabsorbed

Front 52

Filtered Load

Back 52

FL = GFR x P
-small molecules that are filtered w/o impedance are freely filterable
-quantity filtered = filtered load --> depends on plasma concentration of solute & GFR
-ex. Glucose --> GFR = 125 mL/min
--> plasma [glucose] = 100 mg/dL = 1 mg/mL
--> filtered load = (125 mL/min)(1mg/mL) = 125 mg/min

Front 53

Small increase in GFR

Back 53

= large increase in volume fluid filtered & excreted
-GFR highly regulated (between 80-180 mL/min)
-Intrinsic Mechanism
1)Myogenic Regulation
2)Tubuloglomerular feedback
--> both keep rate constant when BP rises (negative feedback)

Front 54

Decrease in BP does what to GFR?

Back 54

-decreases GFR
-driectly --> decrease in filtration pressure
-indirectly --> through extrinsic control

Front 55

Tubular Reabsorption

Back 55

-movement from tubules into peritubular capillaries (return to blood)
-most occurs in proximal tubule (non-regulated/obligatory)
-some occurs in distal tubules (highly regulated)

Front 56

Trans-/Paraepithelial Transport

Back 56

-Barrier for reabsorption --> epithelial cells of renal tubules & endothelial cells of capillary (minimal)

Front 57

Reabsorption

Back 57

recovers useful material from filtrate

Front 58

Secretion

Back 58

-ejects waste product, toxins, & other undesirable solutes
-both reabsorption & secretion occur in every segment of the nephron
-relative importance changes from segment to segment

Front 59

Renal Tubule Specialization

Back 59

-special regions perform special functions
-non-regulated reabsorption in proximal tubule
-Regulated reabsorption and secretion in the distal tubule and collecting duct
-Water conservation in the Loop of Henle

Front 60

Proximal Tubules

Back 60

-the mass reabsrobers
-70% water & sodium
-100% glucose
-brush border provides for large surface area
-non-regulated reabsorption --> leaky tight junctions allow paracellular transport

Front 61

Distal Tubules

Back 61

-transport is regulated across epithelium
-tight junctions limit paracellular transport
-if any part along pathway requires active transport (ATP), then whole pathway is considered active transport

Front 62

Transport Maximum

Back 62

-maximum rate of transport when carriers are saturated
-for a solute which is normally 100% reabsorbed
--> if solute in filtrate saturates carrier --> some excreted in urine
renal threshold = when all carriers are saturated & spill over occurs into urine

Front 63

Glucose

Back 63

-Freely filtered at glomerulus
-Normally 100% actively reabsorbed in proximal tubule
-Normally, no glucose appears in urine
-apical membrane --> secondary active transport
-basolateral membrane --> facilitated diffusion

Front 64

Tubular Secretion

Back 64

-solutes move from peritubular capillaries into tubules
-barriers same for reabsorption
-transport mechanism same, but opposite direction of reabsorption

Front 65

Renal Handling of Inulin (normally not in body)

Back 65

-used in diagnostics --> neither secreted nor reabsorbed
-measures glomerular filration rate

Front 66

Renal Handling of Glucose

Back 66

-100% reabsorbed
-measures reabsorption

Front 67

Reabsorption at DCT

Back 67

-selective reabsorption or secretion primarily along DCT makes final adjustments in solute composition and volume of tubular fluid
-Tubular Cells at the DCT
-Actively transport Na+ and Cl- out of tubular fluid
-Along distal portions:
--> contain ion pumps
--> reabsorb tubular Na+ in exchange for K+

Front 68

Sodium is regulated by...

Back 68

-reabsorption --> regulated by aldosterone & atrial natriuretic peptide
-primary solute in ECF --> critical for osmotic pressure & function of excitable cells

Front 69

Hypernatremia

Back 69

-high plasma sodium

Front 70

Hyponatremia

Back 70

-low plasma sodium

Front 71

Aldosterone

Back 71

-increases reabsorption of sodium (and therefore increases reabsorption of water)
-Steroid hormone
-Secreted from adrenal cortex
-Acts on principal cells of distal tubules and collecting ducts
--> Increases number of Na+/K+ pumps on basolateral membrane
--> Increases number of open Na+ and K+ channels on apical membrane

Front 72

Atrial Natriuretic Peptide (ANP)

Back 72

-decreases reabsorption of sodium (and therefore decreases reabsorption of water)
-Secreted by atrial cells in response to distension of atrial wall = increased MAP
-Decreases sodium reabsorption by closing sodium channels in apical membrane
-Overall effect: increased sodium excretion

Front 73

RAAS system

Back 73

REVIEW

Front 74

Postassium Balance

Back 74

-K+ ions regulated by secretion
-aldosterone
-K+ critical to function of excitable cells
-Glomerulus—freely filtered
-Proximal tubules—reabsorbed (obligatory)
-Potassium secretion in distal tubules and collecting ducts is regulated
-K+ in plasma directly stimulates aldosterone release
-As K+ increases, more aldosterone released

Front 75

Hyperkalemia

Back 75

-high plasma potassium

Front 76

Hypokalemia

Back 76

-low plasma potassium

Front 77

Calcium Balance

Back 77

-triggers exocytosis
-triggers secretion
-triggers muscle contraction
-increases contractility of cardiac & smooth muscle
-organs --> kidneys, digestive tract, bone, & skin
-hormones --> parathyroid hormone & calcitrol

Front 78

Hypercalcemia

Back 78

-high plasma calcium

Front 79

Hypocalcemia

Back 79

-low plasma calcium

Front 80

Parathyroid Hormone

Back 80

-Released from Parathryoid gland
-Stimulus = decrease Ca2+ in plasma
-Actions
--> Increase Ca2+ reabsorption by kidneys
--> Stimulates activation of calcitriol in kidneys
--> Stimulates resorption of bone
--> Stimulates small increase in calcium absorption
-Overall effect: increase blood calcium

Front 81

Calcitonin

Back 81

-Secreted from C cells of thyroid gland
-Release triggered by high plasma [Ca2+]
-Actions at target cells
--> Increase bone formation
--> Decrease calcium reabsorption by kidneys

Front 82

Acid-Base Balance

Back 82

-Normal pH of arterial blood = 7.35–7.45
--> pH < 7.35 = acidosis
--> pH > 7.45 = alkalosis

-Complications with acid-base disturbance
--> Conformation change in protein structure
--> Changes in excitability of neurons
--> Changes in potassium balance
--> Cardiac arrhythmias
--> Vasodilation

Front 83

Input & Output of Acids

Back 83

-Carbon dioxide: volatile acidLactic -acid/ketones: organic acids (anaerobic metaoblism & protein/lipid metabolism)

Front 84

Carbon dioxide/respiratory involvement

Back 84

-Normal PCO2 arterial blood = 40 mm Hg
-Sources of CO2: metabolism
-Output of CO2: through respiratory system
-Increases in plasma [CO2] --> respiratory acidosis
-Decreases in plasma [CO2] --> respiratory alkalosis

Front 85

Metabolic acidosis

Back 85

-Decrease pH through something other than carbon dioxide -->
-High protein diet
-High fat diet
-Heavy exercise
-Severe diarrhea (loss of bicarbonate)
-Renal dysfunction

Front 86

Metabolic Alkalosis

Back 86

-Increase pH through something other than carbon dioxide
-Excessive vomiting (loss of hydrogen ions)
-Consumption of alkaline products (baking soda)
-Renal dysfunction

Front 87

Lines of Defense Againsts pH changes

Back 87

1) Buffering of hydrogen ions
2) Respiratory compensation
3) Renal compensation

-

Front 88

Buffering of Hydrogen Ions

Back 88

-Quickest defense against changes in pH
-Most important ECF buffer = bicarbonate
-ICF buffers --> proteins & phosphates

Front 89

Carbonic Acid–Bicarbonate Buffer System

Back 89

1) Cannot protect ECF from changes in pH that result from elevated or depressed levels of CO2 i.e. cannot protect against changes in the concentration of its own weak acid
2) Functions only when respiratory system and respiratory control centers are working normally
3) Ability to buffer acids is limited by availability of bicarbonate ions i.e. the bicarbonate reserve

Front 90

Respiratory Compensation

Back 90

-Takes minutes to have effect
-Regulates pH by varying ventilation
-Increase ventilation --> decreases CO2
-Decrease ventilation--> increases CO2

Front 91

Respiratory Acidosis

Back 91

-Develops when the respiratory system cannot eliminate all CO2 generated by peripheral tissues
-Primary sign
--> Low plasma pH due to hypercapnia
-Primary cause
--> Hypoventilation

Front 92

Proximal Tubule

Back 92

-Bicarbonate reabsorption coupled to hydrogen ion secretion

Front 93

Distal Tubule & Collecting Duct

Back 93

-Secretion of hydrogen ions coupled to synthesis of new bicarbonate ions

Front 94

Respiratory Alkalosis

Back 94

-Rare Occurrence
-Primary sign
--> High plasma pH due to hypocapnia
-Primary cause
--> Hyperventilation

Front 95

Metabolic Acidosis

Back 95

1)Production of large numbers of fixed or organic acids:
-H+ overloads buffer system
-Lactic acidosis – exercise/prolonged hypoxia
-Ketaocidosis- diet/starvation/diabetes mellitus
-Severe bicarbonate loss – chronic diarrhea

2) Impaired H+ excretion at kidneys

Front 96

Metabolic Alkalosis

Back 96

-Is caused by elevated HCO3- concentrations e.g. prolonged vomiting
-Bicarbonate ions interact with H+ in solution
--> Forming H2CO3
-Reduced H+ causes alkalosis

Front 97

The Medullary Osmotic Gradient

Back 97

-Osmotic gradient is established by the counter-current multiplier
-Dependent on loop of Henle and the Vasa Recta

-Ascending Limb
--> mpermeable to water
--> Active transport of Na+, Cl-, and K+

-Descending Limb
--> Permeable to water
--> No transport of Na+, Cl-, or K+

Front 98

Counter Current Multiplier

Back 98

-caused by selective permeability & selective transport of ions in the loop of Henle
-Fluid in proximal tubule = 300 mOsm
-Fluid in descending limb—osmolarity increases as it descends
--> Osmolarity = interstitial fluid
--> Osmolarity > descending limb
-Fluid in ascending limb—osmolarity decreases as it ascends
--> Osmolarity < interstitial fluid, descending limb

-Creation of a medullary concentration gradient

Front 99

Water Reabsorption in Renal Tubules

Back 99

-70% water reabsorbed in proximal tubule --> Not regulated
-20% reabsorbed in distal tubule --> Regulated by ADH
-10% reabsorbed in collecting ducts --> Regulated by ADH
--> Reabsorption in distal tubules and collecting ducts
Dependent upon the osmotic gradient --> established by counter-current multiplier
-Dependent on epithelium permeability to water
-Water permeability dependent on water channels
-Aquaporin-3: present in basolateral membrane always
-Aquaporin-2: present in apical membrane only when ADH present in blood

Front 100

Regulated Water Reabsorption

Back 100

-When membrane of late DCT and CD is impermeable to water (basal levels of ADH)
--> Water cannot leave the tubules
--> No water reabsorption
--> More water is excreted in urine

Front 101

ADH stimulates...

Back 101

-ADH stimulates the insertion of water channels (aquaporin-2) into apical membrane
-Water is reabsorbed by osmosis
-Maximum urine concentration is 1400 mOsm

Front 102

Regulation of ADH release

Back 102

-ADH = posterior pituitary hormone
-Released from neurosecretory cells originating in hypothalamus
-Primary stimulus for release --> Increased osmolarity (osmoreceptors)
-Other stimuli
--> Increase blood pressure (baroreceptors)
--> Increased blood volume (volume receptors)

Front 103

Micturation

Back 103

-Urination
-Urine formed in renal tubules
-Fluid drains into renal pelvis and into ureter
-Ureters lead to bladder
-Bladder stores urine until it is excreted

Front 104

Micturition Reflex and Urination

Back 104

-As the bladder fills with urine --> Stretch receptors in urinary bladder stimulate sensory fibers in pelvic nerve Begins when stretch receptors stimulate parasympathetic preganglionic motor neurons

-Volume >500 mL triggers micturition reflex

--> Stimulus travels from afferent fibers in pelvic nerves to sacral spinal cord
-Efferent fibers in pelvic nerves (parasympathetic) --> Stimulate ganglionic neurons in wall of bladder

-Interneuron relays sensation to thalamus
-Projection fibers from thalamus deliver sensation to cerebral cortex
external urethral sphincter (skeletal muscle) is under voluntary control

Front 105

Infant Urination

Back 105

-Lack voluntary control over urination
-Corticospinal connections are not established

Front 106

Review Micturation Feedback Chart

Back 106

Urinary Slide 108