EXAM 4 Flashcards
major nutrients
macronutrients: Carbohydrates, lipids, proteins
micronutrients
vitamins + minerals
USDA “my plate” guidelines
-1/2 fruits and vegetables
-1/2 grains and proteins
glass of milk
there are 45-50 essential nutrients
must be in diet for healthy physiology because body doesn’t make enough of it
carbohydrates include
-sugars: mono+disaccharides
—-from fruit, milk, and honey
-polyscaccharides: from grains, fruits, and veg
glucose is used by
-cells for energy
-red blood cells and neurons rely on it
insoluable polysaccharides
-such as cellulose provide fiber that help with intestinal health, defecation
-soluble fibers in some fruit
the most abundant dietary lipid is
-triglycerides: neutral fat
-saturated fat (with hydrogen) in meat+ dairy
-unsaturated: olive oils+seeds
essential fatty acids include
-e.g. linoleic+ linoleic acids are needed in the diet
–in most vegetable oils
cholesterol is found in
-egg yolk, milk, meat
-liver secretions
lipids are used by the body to
-cell membrane stability
-myelin in nervous system
-absorption of fat soluble vitamins
-can provide energy storage+ as an energy source in some conditions
-some chemical messengers: prostaglandins
-make adipose: cushioning and insulation
proteins have all essential amino acids are
-complete proteins : dairy, meat, fish, soybeans
-vs. incomplete proteins: lack four or more of 8 essential amino acids
incomplete proteins:
lack four or more of 8 essential amino acids
amino acids from dietary protein may be used to
-synthesize new proteins or be broken down to make energy
conditions that determine how amino acids are used determine
weather someone is positive in nitrogen balance or negative
to be positive in nitrogen balance (amino acids)
i) all needed amino acids (all 20 of them)
ii) caloric intake of carbs+fats meets energy needs
iii) hormone levels reflect healthy, non stressed states; healthy, low levels of stress hormones and healthy high levels of growth hormones
vitamins mostly serve as
coenzymes (assist in catalysis)
Vitamins A,D,E, and K are
exp for vit a
-fat soluble
-e.g. vitamin A in rhodopsin in rod’s for night vision
water soluble vitamins include
example of a ws vit
B-complex vitamins and vitamin C
folic acid- important for DNA replication in fetal development
water soluble vitamin functions
important in DNA replication
minerals such as Ca+ are used by the body to
-add strength to bones and teeth
-messengers to influence proteins’ function (eg Ca+ binds to calmodulin in smooth m)
-excitability: Ca+ depolarization of heart cells
metabolic processes are either
catabolic: breaking down big molecules
anabolic: building big molecules
catabolic processes
breaking down big molecules
anabolic
building big molecules
In cellular respiration…
food molecules are broken down and their parts are used to make atp
Three stages are involved in processing energy containing nutrients
a) GI system digest nutrients and absorbs them
b) convert small nutrient molecules to a form that can be used for energy production
c) aerobic production of energy in mitochondria
oxidation-reduction reactions are coupled reactions that involve
-transfer of electrons from one molecule to another
-when O added or H is lost it is oxidized
-a molecule that gains an electron is reduced
in the body, oxidation reduction reactions are enzyme catalyzed
-use coenzymes such as FAD and NAD+
-energy from food is transferred to the coenzyme so ATP can be made
ATP synthesis may occur through two mechanisms
-substrate-level phosphorylation
-oxidative phosphorylation
substrate-level phosphorylation
P transferred from one molecule over to ADP to make ATP
oxidative phosphorylation
uses, pushes
-uses electron transport chain in mitochondria
-pushes H+ into intermembrane space
-when H+ diffuses back in energizes the ATP synthase to make ATP
Carbohydrate Metabolism
- glucose enters the cell by….
-facilitated diffusion when insulin causes glucose transporters to go to membrane
Carbohydrate Metabolism
- glucose enters glycolysis
what is it and where does it occur
=sugar splitting, happens in cytosol, no O2 needed
3 phases
Glycolysis Phase 1
investment of 2 ATP to add phosphate groups to glucose
Glycolysis Phase 2
sugar cleavage: the 6-c sugar is split into three carbon fragments
glycolysis phase 3
-3 C fragments are oxidized
-ATP is formed (net of 2 ATP for glycolysis)
-NAD+ is reduced to NADH
two pyruvic acids molecules can follow ____ depending on ____
two distinct pathways depending on the availability of oxygen
pyruvic acid pathways when there is not enough oxygen
pyruvic acid ferments into lactic acid
pyruvic acid pathways when there is adequate oxygen
what (2 things) enters what to start what
pyruvic acid and NADH enter mitochondria to start aerobic cellular respiration
in aerobic pathways, pyruvic acid
enters mitochondria by active transport
pyruvic acid is first converted to
acetyl CoA: One carbon is removed from pyruvate and acetyl CoA is added
Acytyl CoA enters the Krebs Cycle (citric acid cycle)
within…
what combines
what is oxidized
-within mitochondrial matrix
-Acetyl acid combines with oxaloacetic acid to form citric acid
-citric acid is then oxidized
the krebs cycle yields (3)
2 ATP
NADH, FADH2 (reduced coenzymes)
CO2+H+
the electron transport chain
requires, pushes, then what
-requires O2 to take electrons from coenzymes (generates H2O)
-Pushes H+ out of matrix into inter membrane space
-as H+ flows back into matrix, oxidative phosphorylation occurs by ATP synthase
krebs cycle: the net energy gain from one glucose molecule is
30 ATP
cells cannot store large amounts of ATP, and so
they spend it or save its energy in other forms
glycogenesis
whats created
where and when
-creating glycogen from glucose
-occurs in liver and muscle cells when energy levels are high
glycogenolysis
what happens, when
-split glycogen to glucose:6P when energy is low; liver cells can remove the P and release glucose to blood
gluconeogenesis
uses what to make what and when
-use amino acids or glycerol to make glucose in liver when energy is low
energy content of fat molecules is
-very high
-most energy dense type of fuel 9cal/gram
lipolysis
-break down T.A.G. with lipase into glycerol and fatty acids
-followed b-oxidation: breaking off 2-c’s at a time of F.A.; add CoA and enter citric acid cycle
-ketone bodies can be a byproduct
Lipogenesis
-when energy levels are sufficient, energy can be stored as fat
-TAG is built up from smaller molecules
Protein metabolism; amino acids can be used
- to make new proteins
-when all neededamino acids are present
-allows ingested and synthesized a.a.’s to build new proteins
Protein metabolism; amino acids can be used
- for energy
when?
transamination
-when energy levels are low, when stress hormone levels are high, when certain a.a.’s are lacking
-change the amino acid…
–transamination: converts one amino acid into a keto acid
–that keto acid can be modified to enter the citric acid cycle to make ATP
–extra nitrogen can be excreted by kidney at urea
insulin is a key hormone for the…
absorptive state= well fed
during the absorptive state __ exceeds __
anabolism exceeds catabolism
insulins effect on glucose metabolism
-_ glucose uptake by body cells
-__ glucose oxidation in tissue cells
-__ gluconeogenesis
-__storage of glycogen and conversion of carbohydrates to fat
-increase glucose uptake by body cells
-increase glucose oxidation in tissue cells
-decrease gluconeogenesis
-increase storage of glycogen and conversion of carbohydrates to fat
insulins effect on amino acid metabolism
-increase transport of amino acids into cells
-increase protein synthesis
insulin contributes to feelings of
satiety
nuclei (clusters of cells) in the ___ are crucial for eating
hypothalamus
some cells make neurotransmitters or hormones that trigger hunger…
when fasting (i.e. in postabsorbative state)
NPy from arcuate nucleus –> increase orexin from lateral hypothalamic area
other cells make neurotransmitters or hormones that trigger satiety…
after a big meal
POMC+CART from arcute nucleis-> increase CRH from ventromedial nucleus
short-term regulation of food intake
what for hunger and what for satiety?
i) empty stomach secretes ghrelin: hormone that stimulates hunger pathways in brain
ii) full stomach and high blood sugar stimulate vagus nerve and insulin secretion; insulin stimulates satiety pathways in brain
long-term regulation of food intake
i) adipose cells secrete leptin (especially at night)
–leptin inhibits hunger pathways and stimulates satiety pathways
other factors that make impact food intake
temperature, stress, infection, the microbiome (community of bacteria that lives in the gut)
Kidney Functions (5)
-filter blood, remove wastes, maintain blood volume (recall long term BP control), EPO secretion for red blood cell count control, maintain electrolyte levels
Kidney Location
-retroperitoneal
-lumbar region
kidney surface structures
coverings (3), where does hilum face, glands
-Coverings: renal capsule, adipose capsule, renal fascia
-adrenal glands sit on top of kidney
-hilum (indentation) faces medially
Kidney internal structures (5)
-Cortex: outside (under capsule) light color
-medulla (middle): has darkly colored pyramid and lighter renal columns
-lobes: about 9 per kidney, each one is one pyramid and its associated cortex
-calyces: drain pyramids:
—minor calyx for one pyramid
—major calyx drains multiple pyramids
-renal pelvis: funnel a hilum
Kidney internal structures
Renal pelvis
-renal pelvis: funnel at hilum
Kidney internal structures
calyces
-calyces: drain pyramids:
—minor calyx for one pyramid
—major calyx drains multiple pyramids
Kidney internal structures
lobes
quanitity+what does a lobe consist of
-lobes: about 9 per kidney, each one is one pyramid and its associated cortex
Kidney internal structures
Medulla
-medulla (middle): has darkly colored pyramid and lighter renal columns
Kidney internal structures
Cortex
(under capsule) light color
Blood vessel Mapping
Nephron and conducting duct
order (5)
a) glomerular capsule (bowman’s)
b) proximal convoluted tubule (PCT)
c) nephron loop (henle)
d) distal convoluted tubule (DCT)
e) collecting duct
Nephron and conducting duct
a) glomerular capsule (bowman’s)
a) glomerular capsule (bowman’s)
Where filtration occurs: fluid moves from glomerular capillary to glomerular capsule
Nephron and conducting duct
b) proximal convoluted tubule (PCT)
b) proximal convoluted tubule (PCT)
both reabsorption and secretion occur here
Nephron and conducting duct
c) nephron loop (henle)
c) nephron loop (henle)
-descending limb- H2O reabsorbed
-accesending limb- Na+ reabsorbed
Nephron and conducting duct
d) distal convoluted tubule (DCT)
-some reabsorption and secretion occurs
Nephron and conducting duct
e) collecting duct
-collects some filtrate from multiple nephrons
-some reabsorption+ secretion
Kidney Physiology
Three procesess
Filtration, Absorption, Secretion
Step 1: Glomerular Filtration
Glomerular Filtration is a __,___ process in which__
Glomerular Filtration is a passive, nonselective process in which hydrostatic pressure of blood pushes fluid through filtration membrane
Step 1: Glomerular Filtration
The Net Filtration Pressure (NFP) responsible for filtrate formation is given by the balance of
HP-OP (hydrostatic pressure and osmotic pressure)
NFP= Glomerulur HP (BP)- Capsular HP (Filtrate P)- Osmotic P (solute concentration in plasma)
Step 1: Glomerular Filtration
The Glomerular Filtration Rate (GFR) is
around 120mL/min
-amount of filtrate formed in capsule in one minute
Step 1: Glomerular Filtration
Maintenance of a relatively constant GFR is important because
reabsorption of solutes and water depend on how quickly filtrate flows through tubules
Step 1: Glomerular Filtration
GFR depends (directly) on
1) permeability of glomerular membrane
2) size of glomerular membrane
3) NFP: net filtration pressure
Step 1: Glomerular Filtration
GFR Is held constant through multiple mechanisms
a)renal autoregulation
i) myogenic mechanism- afferent arterioles respond to changes in pressure-> they dilate or constrict to compensate
ii) tubuloglobmerlur mechanism: change in local messenger levels (vasoactive chemicals) acting on afferent arterioles in response to flow (speed and saltiness) in nephron
a)renal autoregulation
i) myogenic mechanism
i) myogenic mechanism- afferent arterioles respond to changes in pressure-> they dilate or constrict to compensate
a)renal autoregulation
tubuloglobmerlur mechanism
ii) tubuloglobmerlur mechanism: change in local messenger levels (vasoactive chemicals) acting on afferent arterioles in response to flow (speed and saltiness) in nephron
Step 1: Glomerular Filtration
GFR Is held constant through multiple mechanisms
b) Extrinsic Neural Mechanisms are stress-induced sympathetic responses that inhibit filtrate formation by
constricting afferent arterioles thus lowering NFP thus lowering GFR
Step 1: Glomerular Filtration
GFR Is held constant through multiple mechanisms
c) the renin-angiotestin mechanism
-kidney reacts to Low BP by secreting renin
-renin triggers a cascade that helps raise blood volume+ systemic vasoconstriction so that BP rises and thus GFR raises to normal
Step 2: Tubular Reabsorption
Tubular Reabsorption
occurs where (2 places )
retains what
-occurs both paracellularly and transcellularly
-retains viable nutrients, needed H20, and some electrolytes
Step 2: Tubular Reabsorption
The most abundent cation of the filtrate is __ and resabsorption is usually active
where is the Na+ K+ pump
SODIUM
-Na+/K+ pump on basolateral membrane of tubual walls
Step 2: Tubular Reabsorption
Obligatory Water Reabsorption occurs in the___where
In P.C.T. water returns to bloodstream by osmosis
Step 2: Tubular Reabsorption
Secondary active transport is responsible for absorption of
glucose, amino acids, most cations, and occurs when solutes are co transported with Na+
a) the Na+ in the cotransporter is moving down its concentration gradient
Step 2: Tubular Reabsorption
different areas of the tubules have different
absorpative capabilities
Step 3: Tubular secretion
Tubular secretion disposes of
unwanted solutes
-excess H+, K+, sometimes drugs
Step 3: Tubular secretion
Tubular Secretion Is most active in
PCT but is also in other parts of the tubule
Regulation of Urine Concentration and volume
one of the critical kidney functions is to keep the solute load of body fluids by
by regulating urine concentration and volume
300m 0sm
Regulation of Urine Concentration and volume
The countercurrent mechanism involves interaction between
between filtrate through the limb of nephron loops (henle)
what is freely absorbed by the descending limb of the loop of henle
water
since water is freely absorbed by the descending limb of the loop of henle FILTRATE CONCENTRATION ___and water is ___
FILTRATE CONCENTRATION increases and water is reabsorbed
the ascending limb is permeable to ___ but not to ___
the ascending limb is permeable to solutes but not to H2O
In the collecting duct, urea diffuses into the ___, contributing to
diffuses into the deep medullary tissue, contributing to the increasing osmotic gradient ecountered by the filtrate as it moves through the loop
Production of a dilute urine occurs when
where does the collecting duct carry the dilute urine to
-overhydrated SO
-decreased ADH secretion
-the collecting duct carries dilute urine towards minor calyx w/o much reabsorption of H2O
formation of concentrated urine occurs when
more adh causes– what is it called
-when under-hyrdrated
-the pituitary secretes more ADH causing insertion of more aquaporins into walls of conducting duct
-this is falutative H2O reabsorption
Diuretics act to
a) inhibiting Na+ reabsorption, thus less H2O reabsorption
b) decreased ADH will increase urine output (eg. alcohol, diabetes insipidus)
c) if other solutes are in urine (e.g. diabetes militus: lots of glucose in filtrate)
Renal Clearance
Clearance refers to the volume
volume of plasma that is cleared of a specific substance in a given period of time mL/min
Renal Clearance
Inulin is a useful plant polysaccharide (to measure GFR) for this because inulin
renal clearence equation
-inulin is filtered but not reabsorbed nor secreted (mg/mL)
R.C.=u*v/ p
u=conc of test substance in urine
v= urine output over time mL/min
p= plasma conc of test substance (mg/mL)
if the clearance value is greater than the inulin clearance rate, then
substance is secreted
Ureters (2)
location, length
wall
-retroperitoneal, 1 ft long
-from kidney to bladder
WALL
-mucosa: transitional epithelium+lamina propria
-smooth m of muscularis
-adventitia: connective tissue
urinary bladder
location, 2 things it consists of
wall
-retroperitoneal, behind pubic symphysis
-rugae: folds
-trigone: region of bladder floor, opening of two ureters+ 1 urethra
WALL
-mucosa: transitional epithelium
-smooth m= detrusor m.
-adventitia: connective tissue
urethra
from where to where
lining (3)
-tube from bladder to outside body
-its lining: transitional epithelium->pseudostratified-> stratified squamous
Micturation or urination is the act of
emptying the bladder
voluntary initiation of voiding reflexes results in the activation of the micturation centers of the __ which signals the ___neurons that stimulates contration of the __ and relaxation of___
-what are the things at the bottom of the bladder
-what does the somatic nervous system need to do
voluntary initiation of voiding reflexes results in the activation of the micturation centers of the PONS which signals the PARASYMP neurons that stimulates contration of the DETRUSER M. and relaxation of the URINARY SPHINCTER
-internal urethral spincters of smooth m. (at bottom of bladder)
-somatic nervous system needs to relax the skeletal m. of the external urethral sphincter
Body water content
Total body water muscle vs fat
Fat only- 20% of water
Muscle- 75% of water
Body water content
Age
Infants- 75% H2O
Older adults- 50% H2O
Body water content
Gender
Male - 60% H2O
Female- 50% H2O
Fluid Compartments
two main fluid compartments inbody
2/3 of H2O is intracellular
1/3 of H2O is exracellular
Fluid Compartments
there are two subcompartments of the extracellular fluid
80% of extracellular fluid is interstitial
20% contains blood plasma
Composition of bodily fluids
nonelectrolytes include most
most organic moleules, do not dissociate in water, and carry no electrical charge (e.g. glucose)
Composition of bodily fluids
Electrolytes are
-are more numerous but less massive
-dissociate into ions in water
-include: salts, acids, and bases
-important contributers to osmotic pressure
–1m NaCl is a 20sm solution
-important ions include: Na+, K+, Cl-,Ca+
For proper hydration, water intake must equal
WATER INTAKE
water output
water intake: food+water that has been ingested, cellullar metabolism (condensation rxns)
Water Output
insensible losses include
-urine, feces, sweat
-insensible losses: breathing, osmosis through skin
the thirst mechanism is controlled by
what contributes to feelings of thirst
the hypothalamic thirst center
a) osmoreceptors detect high Osm of plasma
b) low BP, dry mouth, high levels of angiotestin 2, empty stomach can all contribute to feelings of thirst
regulation of water output
obligatory water loss
-mainly controlled by ADH (which limits output)
-but some water loss in urine is obligatory, as is loss of water vapor in breath
the amount of water reabsorbed in the renal collecting ducts is proportional to
ADH release
Influence of ADH
When ADH levels are low, most water in the collecting ducts..
is not reabsorbed, leading to high quantities of dilute urine
Influence of ADH
When ADH levels are high, filtered water is
reabsorbed, resulting in a lower volume of concentrated urine
ADH secretion is promoted or inhibited by the ____ in response to (3 things)
the hypothalamus in response to changes in solute concentrartion of extracellular fluid, large changes in blood pressure or volume, or vasular baroreceptors
Dehydration occurs when
water out> water in
-cells shrink
-weight loss, confusion, shock
Hypotonic hydration results from
- decreased Osm of ECF
-cells swell
-water intoxication, hyponatremia, renal insufficiency
edema is the accumulation of fluid in the
possible causes
extracellular space
a) high capillary BP (e.g. in heart failure)
b) hyponatermia- thus low osmotic p
c) lymphatic impairment- extreme example is filariasis (“elaphentitis”)
The central role of sodium in fluid and electrolyte balance
important to regulation due to its abundence in osmotic pressure
Regulation of sodium balance
when aldosterone secretion is high, nearly all filtered sodium
nearly all filtered sodium is reasbsorbed in the distal convoluted tubule in and the collecting duct
increased aldosterone= increased sodium reabsorption
the most important trigger for the release of aldosterone is the
response to 3 things
renin-angiotestin mechanism, initiated in response to sympathetic stimulation, decrease in filtrate osmolarity, or decreased blood pressure
cardiovascular baroreceptors monitor
blood volume so that blood pressure remains stable
Atrial Natriuretic Peptide reduces blood pressure and blood volume by
inhibiting release of renin, aldosterone, ADH and stimulating vasodialation
Estrogens are chemically similar to aldeosterone and enhance
reabsorption of Na+ in kidney
Glucocorticoids such as cortisol___Na+ reabsoprtion
increase
potassium is crucial to the maintenence of
the membrane potential of neurons and muscle cells,
and is a buffer that compensates for shifts of hydrogen ions in or out of cells
both hypo and hyperkalemia can cause irregular heart rhythm
Aldosterone influences K+ pump secretion as
it adds Na+/K+ pumps to kidney tubules thereby increasing K+ secretion
Because of the abundence of hydrogen bonds in the body’s functional proteins, they are strongly influenced by
hydrogen ion concentration
When arterial blood pH rises above 7.45 it is
Alkalosis
When arterial blood pH drops below 7.35 it is
acidosis
Most hydrogen ions originate as
metabolic byproducts of CO2 or breakdown of fats
A chemical buffer is a
set of molecules suh as weak acid-weak base pair that resists change of pH
The bicarbonate buffer system is the main buffer of
extracellular fluid and consists of a carbonic acid and its salt, sodium bicarbonate
The bicarbonate buffer system
when a strong acid is added to the solution
bicarbonic ions bind much of the H+ that came off the strong acid
The bicarbonate buffer system
when a strong base is added to the solution
-carbonic acid donates more H+ to bing the OH- of the strong base
the protein buffer system
is main system inside cells
-proteins are amphoteric-can be weak acids or bases
-COOH (carboxyl) groups can donate H+, NH3 groups (amine) can accept H+
When hypercapnia occurs, pH drops, activating respiratory centers, resulting in
increased ventilation to blow off more CO2 (returning pH up to normal)
When pH rises, the respiratoru centers are depressed, allowing
CO2 to accumulate in the blood, lowering pH to normal
Renal mechanisms of acid-base balance
bicarbonate ions can be converted from filtrate or synthesized by
Type A intercalated cells in response to acidosis
Renal mechanisms of acid-base balance
when the body is in alkalosis,
type B intercallated cells excrete bicarbonate, and reclaim hydrogen ions
Abnormalities of acid-base balance
respiratory acidosis is characterized by
a rise in CO2 that lowers blood pH
-often caused by brreathing disorders
Abnormalities of acid-base balance
respiratory alkalosis is characterized by
low CO2 that causes pH to rise= hyperventilations
-often caused by anxiety or being at altitude
Metabolic acidosis is characterized by
any drop in blood pH not caused by a breathing problem e.g. diarrhea
metabolic alkalosis is indicated by
any rise in blood pH not due to breathing
e.g. constipation or vomiting
Abnormalities of acid-base balance
Compensations
to deal with pH disturbances, physiologically the kidneys adjust H+ anhd HCO3- (BICARB) secretion+ reabsorption while respiratory system adjusts breathing depth and rhythm
