Kinesiology 10

Front 1

renal cortex

Back 1

outer region of kidney, where renal artery divides into many branches, supplying blood to nephrons located in the cortex- nephrons in the renal cortex means that this is where the majority of renal filtration takes place

Front 2

renal medulla

Back 2

location of the collecting ducts, where nephrons empty their contents

Front 3

nephron

Back 3

tubular structures within kidney that are specialized for transport of water and solutes between interstitial fluid and urinary filtrate

Front 4

glomerulus

Back 4

large tuft of specialized capillaries specialized for fluid filtration. glomerulus is located within bowmans capule of each nephron.

Front 5

podocyte

Back 5

octopus-like large structures surrounding the glomerular capillary basement membrane and serving as a barrier to large molecular solutes - part of the filtration structure of the glomerulus.

Front 6

bowmans capsule

Back 6

interior of the cuplike structure surrounding the glomerulus at the end of each tubular membrane.

Front 7

proximal tubule

Back 7

FUNCTION: ABSORPTION
tubule closest to the glomerulus, responsible for reabsroption of low molecular weight molecules important to metabolism, and water.

Front 8

distal tubule

Back 8

FUNCTION - SECRETION
major regulator of Na+ and water excretion, and K+.

Front 9

afferent arteriole

Back 9

carries arterial blood to glomerulus

Front 10

efferent arteriole

Back 10

carries blood flowing from the glomerulus to the peritubular capillary.

Front 11

peritubular capillaries

Back 11

surround the tubular portions of the nephron and are important in reabsorbing and excreting products from and to the interstitial space to assist the nephron in carrying out its function

Front 12

Loops of henle

Back 12

concentrates urine through a counter-current multiplier system - concentrated at tip, dilute at base.

Front 13

proximal convoluted tubule

Back 13

completely reabsorbs metabolically useful molecules, secretes others (urea, creatinine, histamine, penicillin)

Front 14

collecting duct

Back 14

where nephrons merge to carry end products of tubules via the ureter, to the bladder

Front 15

ureter

Back 15

tubes leading from kidneys to bladder which carry waste products to be expelled from the body

Front 16

bladder

Back 16

temporary storage point for urinary waste products before urination

Front 17

urethra

Back 17

tube runs from bladder --> outside, through which urine is expelled.

Front 18

How much fluid is reabsorbed, and at what rate?

Back 18

99% is reabsorbed:
110ml of water in = 1 ml of urine out.

Front 19

rate of bloodflow through organs expressed how?

Back 19

pressure in - pressure out/resistance = blood flow.

Front 20

glomerular filtration rate

Back 20

volume of fluid filtered in one minute through the glomerulus. on average, about 20% of the total volume of plasma passing through the glomerulus.

Glomerular filtration is because of fluid pressure differentials, forcing blood plasma out of the capillaries of the glomerulus and into bowman’s capsule

Front 21

tubular reabsorption

Back 21

tubular cells taking filtered molecules from tubular fluid and placing them back into the interstitial fluid

Front 22

tubular secretion

Back 22

tubular cells carry molecules that have diffused out of the peri-tubular capillaries INTO renal tubular fluid.

Front 23

excretion

Back 23

total filtration, less reabsorption, PLUS secretion = excretion.

Filtration = about 20% of blood going through glomerulus.

Less reabsorption = molecules that are sent back into interstitial space and reabsorbed into the blood via the peritubular capillaries.

Plus secretion = molecules that pass from blood TO urine (creatinine, penicillin, histamine, urea, etc.)

Front 24

plasma colloid pressure

Back 24

inherent pressure of the plasma due to the continued presence of large ions, proteins and other molecules that can't readily diffuse out.

Front 25

hydrostatic pressure

Back 25

effected by arteriole pressure (both efferent and afferent) hydrostatic pressure in the glomerulus effects glomerular filtration rates. The pressure exerted by the blood plasma. This pressure assists in forcing the filtration of plasma through the glomerular capillaries. At about 60mg Hg, this is much higher within the kidneys than in any other somatic capillary

Front 26

net filtration pressure

Back 26

Within the glomerulus, net filtration pressure is the resultant pressure through the capillaries, taking the gross input pressure minus the opposing forces. The opposing pressure forces are the colloid osmotic pressure of the plasma, plus the inherent hydrostatic pressure of the bowman’s capsule

Front 27

renal blood flow

Back 27

fluid filtered through the glomerular capillaries- helps to determine renal function

Front 28

inulin

Back 28

- polysaccharide
-not normally found in plasma
- used as a way of measuring glomerular filtration rates
- nontoxic
-Filters through the glomerulus and is neither absorbed nor secreted
- THEREFORE, 100% of inulin filtered = GFR.

Front 29

Na+ K+ pump

Back 29

maintains Na+ K+ concentrations in proximal tubular cells which allows reabsorption of metabolic products from glomerular filtrate.

Front 30

glucose reabsorption

Back 30

1mg/ml = 100 mg glucose filtered / minute. Usually ALL glucose is reabsorbed.

Front 31

renal threshold

Back 31

plasma glucose level at which glucose begins to escape complete reabsorption and enter urine. (as in diabetes.)

Front 32

osmotic diuresis

Back 32

increases in solute concentration necessitates additional water to carry solutes away. Increases in solute excretion causing additional water and diuresis is osmotic diuresis.

Front 33

urea

Back 33

solute normally found in plasma which is filtered and mostly reabsorbed.

Front 34

acidosis

Back 34

if GFR falls to below normal rates, kidneys ability to secrete acid is reduced. Acid is retained, body pH fluid falls, body functions may not work properly.

Front 35

vasopressin / antidiuretic hormone (ADH)

Back 35

hormone inhibits diuresis
synthesized by hypothalamus.
stored in posterior pituitary.

Front 36

aldosterone

Back 36

secreted by cortical layer of adrenal gland
stimulates activity of Na+K+ transport --> important regulator of BLOOD PRESSURE

Front 37

renin

Back 37

protein which initiates reactions in renin-angiotensin system. Causes the formation of angiotensin I from angiotensinogen, secreted by the liver.

Front 38

Angiotensin converting enzyme: ACE

Back 38

ACE, angiotensin converting enzyme has an important role in determining blood pressure, as it splits angiotensin I to produce angiotensin II, which increases blood pressure by constricting small vessels. The lungs contain the highest concentration of ACE in the body and it is here that the majority of angiotensin is converted by ACE, however ACE is also present in most other cells of the body

Front 39

renin angiotensin system
REGULATES BLOOD PRESSURE.

Back 39

1. Kidney senses low blood pressure or reduced Na+ filtration of glomerulus
2. kidney secretes renin
3. liver continuously secretes angiotensinogen to blood.
4. renin contacts angiotensinogen in blood, it becomes angiotensin I
5. Angiotensin I contacting ACE (present in most cells, but highest concentration in lungs) converts it to Angiotensin II
6. Angiotensin II causes:
- vasoconstriction of small vessels (rise in blood pressure)
- Increased ADH secretion by posterior pituitary = increased thirst --> increased thirst = increased: drinking + fluids --> increased blood pressure
- increased ALDOSTERONE secretion by Adrenal gland --> SALT reabsorption and potassium secretion increase by KIDNEY--> INCREASES BLOOD PRESSURE.

Front 40

diabetes insipidus

Back 40

causes high volumes of urine production - can't drink enough to keep up -> this causes LOW blood pressure. No irregularity of glucose in blood plasma, urine, nor any impairment of insulin secretion.
CAUSED BY LACK OF ADH (ANTI-DIURETIC HORMONE) production by hypothalamus, so PREVENTION of urination doesn't happen.

Front 41

osmoreceptors

Back 41

receptors in brain which sense osmolality of plasma, which serves as information which influences secretion rates of ADH.

-->Plasma osmolality up, ADH up, Urine down.

more concentrated urine = more diluted bodily fluids = plasma osmolality down to normal.

Front 42

Atrial natriuretic peptide (ANP)

Back 42

released when atrial stretch-receptors sense too much blood volume. Causes kidney to excrete more Na+, and therefore more H2O, bringing blood volume back down to normal.

Front 43

countercurrent multiplier system

Back 43

system in the nephrons which concentrates urine through the exchange of ion back and forth across the interstitial space between close together parallel tubules.

Front 44

dialysis

Back 44

separating fluids by a selectively permeable membrane which is bathed in an ideal plasma substitute so that water and small solutes pass across the membrane, thus filtering out. Filters out K+, urea, etc.

Front 45

diuretics

Back 45

class of drugs which, through the inhibition of Na+ transport through renal tubules, cause increased natriuresis (salt excretion) as well as increased overall urine excretion by the kidneys. The resultant decrease in blood volume is effective for lowering blood pressure. Thus, diuretics are used to treat both hypertension and heart disorders

Front 46

mechanism which maintains acid-base balance in the body

Back 46

kidneys secrete acid into tubules along the length of the nephron.

Front 47

hypertension effects on urine production

Back 47

increased pressure = increased fluid volume = atrial release of atrial natriuretic peptide = increased excretion of Na+, H2O, i.e. MORE urine production.

Hypotension = opposite effect.

Front 48

GLOMERULAR FILTRATE COMPONENTS

Back 48

Albumin
glucose
amino acids
urea
sodium
potassium
creatinine
H+

Front 49

Nephron components

Back 49

Afferent arteriole
efferent arteriole
glomerulus
bowmans capsule
proximal tubule
peritubular capillaries
distal tubule
loop of henle
collecting duct

Front 50

Structural factors which allow filtration through glomerulus

Back 50

1. glomerulus being served not by one but by TWO arterioles, resulting in a HIGHER than normal pressure going into the glomerulus.
2. despite the thickness of the filtration barrier made up of the:
- podocytes which restrict cell filtration
- basement membrane which blocks proteins and large solutes, and
- the interdigitating foot processes of the podocytes, this barrier remains PERMEABLE, physically allowing filtration

Front 51

Pressure gradients which allow glomerular filtration

Back 51

pressure of the arterial blood coming in does so at a higher pressure, of about 60 mm Hg. There are inherent pressures within the structure of the glomerulus, however. The bowmans’ capsule has an inherent pressure of about 20 mm Hg, while the colloid osmotic process creates an opposing force of about 30 mm Hg. The incoming pressure of 60 mm Hg, versus the 50 mm Hg of opposing pressures, means that there is still a net pressure of 10 mm Hg which is forcing the capillary filtration of the glomerulus

Front 52

Diabetes mellitus symptoms

Back 52

sugary urine
high urine flow
can't drink enough
improper insulin levels
too much glucose for kidney to reabsorb
trouble maintaining plasma osmolality

Front 53

Diabetes insipidus

Back 53

NOT sugary urine
high urine flow
have trouble drinking enough
INSULIN FINE
glucose uptake fine
VERY LOW blood pressure
ADH levels low --> urination not being prevented by hypothalamus hormone.

Front 54

How glucose absorbed out of proximal tubule?

Back 54

Na+ concentration HIGHER in tubular fluid than in cells lining tubule --> allows glucose transport via facilitated diffusion of Na+ with Na+'s carrier molecule.

glucose then goes into interstitial fluid, and into peritubular capillaries (blood) --> is completely reabsorbed.

Front 55

decrease in aldosterone affect water reabsorption and sodium reabsorption how?

Back 55

decreased Na+ reabsorption, increased K+ absorption. Decreased Na+ = decreased H2O. If 20% of water is lost, death results.

Front 56

Increased Aldosterone production causes?

Back 56

increased Na+ retention
increased H2O retention
increased fluid/blood volume
increased blood pressure - hypertension.