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Bioweek5Urinary
Quiz
58
Biology
Undergraduate 1
02/13/2013

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Term
Renal hilium
Definition
- indent where ureter emerges along w/ blood vessels, lymphatic vessels and nerves
Term
Urinary Systems
Definition

1. Kidney - produces urine

2. Ureters - transports urine fr. the kidney to the bladder

3. Urinary bladder - provides a temporary storage reservoir for urine; 700-800ml capacity

4. Urethra - transports urine fr. the bladder out of the body

Term
Functions of Kidney
Definition

- controls composition and volume / pressure of blood by regulating:

- blood ion composition (Na+, Cl-, Ca2+, etc)

- blood osmolarity (+300mOsm/L - dissolved solutes)


- controls blood pH - regulation of H+ and HCO3-


- regulates blood glucose levels (gluconeogenesis)


- removes wastes fr. the blood (urea, uric acid)


- production of hormones (calcitrol and erythopoitin)

Term
Layers that support the Kidney
Definition

1. renal capsule - deep fibrous layer

- continuous w/ outer coat of ureter

- barrier against trauma and infection

- maintains kidney shape


2. adipose capsule


3. renal fascia

Term
Internal anatomy of Kidney
Definition

1. renal cortex - outer zone of the kidney

- renal columns are portions of cortex that extend bet. renal pyramids

 

2. renal medulla - inner region

- several renal pyramids

 

 

Term
Path of urine drainage
Definition

- collecting duct

- papillary duct in renal pyramid

- minor calyx

- major calyx

- renal pelvis

- ureter

- urinary bladder

Term
Arterial and venous flow out of the kidneys
Definition

- renal artery

- segmental arteries

- interlobar arteries

- arcuate arteries

- interlobular arteries

- afferent arterioles

- glomerular capillaries

- efferent arterioles

- peritubular capillaries

- interlobular veins

- arcuate veins

- interlobar veins

- renal vein

Term
Nephron
Definition

- structural and functional units of kidney that form urine

- each kidney contains = 1 mil nephrons

- consists of a vascular and tubular component

Term
Nephron consists of 2 parts
Definition

1. Renal corpuscle - filters blood plasma

a. glomerulus - capillary network

b. bowman's capsule

 

2. Renal tubule

a. proximal convoluted tubule

b. loop of Henle (descending & ascending)

c. distal convoluted tubule

Term
2 types of Nephrons
Definition

1. cortical nephrons - most common

 

2. juxtamedullary nephrons - loops of Henle extend into the medulla

- formation of very concentrated urine

Term
Urine Formation
Definition

1. glomerular filtration

- filtration fr. blood plasma into nephron

 

2. tubular reabsorption

- fr. fluid in renal tubule into blood

 

3. tubular secretion

- fr. blood into fluid in renal tubule

Term
Glomerular filtration
Definition

- the use of pressure to force fluids and solutes through a membrane

- a passive event cause by:

- very efficient because:

- the porous capillaries, along w/ capsule cells (podocytes) are permeable to H2O and small solutes but not to blood cells or large mol. such as plasma proteins




Term
GF is a passive event cause by:
Definition

- blood pressure that is greater in capillaries than the fluid pressure in the capsule

 

- pressure forces fluid (filtrate) into the capsule

Term
GF is very efficient because:
Definition

1. capillaries present a large surface area

 

2. the filtration memb. is thin and very permeable

Term
Porous capillaries
Definition
- are permeable to H2O and small solutes but not to blood cells or large mol. such as plasma proteins
Term
Glomerular Filtration rate + substances
Definition

- 105-125 mL/min of fluid that is isotonic to blood

 

- substances include H2O and all solutes present in blood (except proteins) including ions, glucose, amino acids, creatinine, uric acid

Term
Regulation of Filtration
Definition

1. constriction or dilation of the AFFERENT and EFFERENT arterioles regulates:

a. blood flow in & out of the glomerulus

b. glomerular capillary surface area available for filtration


2. if the filtration rate is too HIGH

- essential subs. can't be reabsorbed quickly enough and are lost in the urine


3. if the filtration rate is too LOW

- everything is reabsorbed, including wastes that are normally disposed of

Term
3 mechanisms control GF
Definition

1. renal autoregulation

- under normal cond., nephrons can adjust their own filtration rate and blood flow

- this ensures stable fluid & electrolyte bal. in body in spite of significant changes in BP

 

2. neural regulation

3. hormonal regulation

Term
Tubular Reabsorption
Definition

- 99% of H2O & most of the solutes of the filtrate are returned to the blood stream

- 65% reabsorption takes place in PCT

- 16% of filtrate reabsorbed fr. the loop of Henle

- 10-15% of filtrate is reabsorbed in the DCT

- 5-9% reabsorbed in collecting duct


- all organic nutrients are reabsorbed

- H2O & ion reabsorption is hormonally controlled

- may be an active (requires ATP) or passive process

- Na+ reabsorption almost always active

Term

Proximal Convoluted Tubule

REABSORPTION

Definition

- reabsorption (into blood) of filtered:

 

- H2O = 65% by osmosis

- Na+ = 65% by Na/K pump, symporters, antiporters

- K+   = 65% by diffusion

- Glucose = 100% by symporters & facilitated diffusion

- Amino acids = 100% by same above

- HCO3- = 80-90% by facilitated diffusion

- Urea = 50% by diffusion

Term

Loop of Henle

REABSORPTION

Definition

- reabsorption (into blood) of:

 

- H2O = 15% by osmosis in descending limb

- Na+ = 20-30% by symporters in ascending

Term

Early Distal Convoluted Tubule

REABSORPTION

Definition

- reabsorption (into blood) of:

 

- H2O = 10-15% by osmosis

- Na+ = 5% by symporters

- Cl-   = 5% by symporters

Term

Late DCT and Collecting Duct

REABSORPTION

Definition

- reabsorption (into blood) of:

 

- H2O = 5-9% stimulated by ADH

- Na+ = 1-4% stimulated by aldosterone

- HCO3- = variable amnt., depends on H+ secretion

- Urea = variable

Term
Tubular Secretion
Definition

- some subs. are actively secreted fr. blood into tubules for excretion

- H+, K+, ammonia, creatinine, drugs, etc.

Term
Tubular Secretion is important for:
Definition

1. disposing of subs. not already in the filtrate

2. eliminating unwanted subs. such as urea & uric acid

3. ridding the body of excess K+

4. controlling blood pH

Term
PCT SECRETION
Definition

- H+ = variable by antiporters

- NH4+ = variable, increases in acidosis by antiporters

- Urea = variable by diffusion

- Creatinine = small amount

Term

LATE DCT & COLLECTING DUCT

SECRETION

Definition

- K+ = variable amount

- H+ = variable amounts to maintain acid/base homeostasis

 

- ADH levels control concentration of fluid in collecting

Term

LOOP OF HENLE

SECRETION

Definition

1. descending

- permeable to H2O

- impermeable to NaCl

 

2. ascending

- contains active transport mechanisms to reabsorb Na+

- impermeable to H2O


*H2O is not automatically coupled to reabsorption of solutes in this structure


*Independent regulation of both vol. & osmolarity of body fluids

Term
2 Hormonal control of urine volume and composition:
Definition

1. Antidiuretic hormone


a. regulates H2O reabsorption by increasing the H2O permeability of cells in DCT & collecting duct


b. produced in the hypothalamus & released by the posterior pituitary


c. main stimulus for ADH release is an increase in plasma osmolarity

 

2. Aldosterone


a. stimulation of Aldosterone secretion is due to a decrease in blood vol: decrease in plasma Na+, increase in plasma K+


b. juxtaglomerular cells secrete the enzyme RENIN into blood


c. blood pressure decrese: RENIN > angiotensin II > aldosterone



 

Term
Explain regulation of ADH secretion
Definition

- through NEGATIVE FEEDBACK

 

- results of ADH action:

- blood vol. increases

- blood osmolarity falls

 

- urine vol. decreases

- urine solute conc. increases


- so the release of ADH is triggered when osmoreceptor cells in the hypothalamus detect an increase in the osmolarity of the blood

Term
Osmolarity
Definition

- the osmotic conc. of a solution

- total # of solute particles per liter (mOsm/L)

- body fluids = 300 mOsm/L

Term
Explain regulation of ALDOSTERONE
Definition

- stimulates:

- reabsorption of Na+ and Cl-

- H2O reabsorption

- secretion of K+ & H+ in the collecting ducts


- consequences:

- decreased H2O excretion (urine vol.)

- increased Na+ and Cl- conc. in blood

- an increased blood vol.


*juxtaglomerular apparatus (JGA) responds to low blood vol. or blood p. (due to dehydration or loss of blood)

Term
ADH vs Aldosterone
Definition

- both increase H2O reabsorption

 

- but ADH responds to an increase in blood osmolarity due to dehydration or salty foods

 

- while Aldosterone responds to a decrease in blood p. / blood v. due to loss of blood through injury or diarrhea

- increase in plasma K+

Term
Formation of Dilute Urine
Definition

- filtrate is diluted in the ascending loop of Henle

 

- created by allowing this filtrate to continue into the renal pelvis

 

- occurs as long as ADH secretion is kept very low

Term
Formation of Concentrated Urine
Definition

- due to increase in ADH secretion

- causes an increase in the aquaporins in the memb. of the cells lining the DCT and CD

 

- in the presence of ADH, 99% of H2O in filtrate is reabsorbed

Term
Chemical Composition of Urine
Definition

- 95% H2O and 5% solutes

- nitrogenous wastes: urea, uric acid, creatinine

- normal solutes: Na+, K+, HPO3-, sulfate ions, Ca+, Mg+, HCO3-

Term
Nervous control of Micturition
Definition

1. stretch receptors

- signal micturition center in sacral spinal cord to trigger micturition reflex

 

2. micturition reflex

- reflex signal to smooth muscle in bladder wall, & to internal sphincter

 

3. involuntary: bladder wall contracts while internal sphincter relaxes

 

4. voluntary control: external sphincter relaxes then urine is voided

Term
Methods used to replace kidney function
Definition

1. hemodialysis

 

2. peritoneal dialysis

 

3. renal transplantation

Term
Dialysis Therapy
Definition

- when kidneys are impaired the blood needs to be filtered by artificial means to regulate blood composition

 

- haemodialysis, peritoneal dialysis

 

Term
Haemodialysis
Definition

- blood is pumped fr. the arteriovenous fistula into a dialyzer

 

- in the dialyzer, waste products filter fr. the blood thru an artificial memb. into a fuild called the dialysate

 

- purified blood is pumped fr. the dialyzer into the arteriovenous fistula

Term
Peritoneal Dialysis
Definition

- fluid drains or is pumped into the peritoneal space

 

- fluid and waste products are drained fr. the peritoneal space

Term
Dialysis therapy Drawbacks
Definition

- anticoagulants need to be added to the blood

- slow process 15 hr per week

- bet. treatments symp. of uremia reappear

- risk of blood-borne infections

- risk of peritonitis

Term
Kidney Transplant
Definition

- placed in the pelvis, below iliac crest

- most satisfactory solution for patients w/ irreversible kidney failure

- tissue typing needs to be done to find a good match bet. donor and recipient

- immunosuppressive drugs are given to reduce tissue rejection

Term
Anuria
Definition

- total absence of urine

Term
Oliguria
Definition
- very little or scanty urine
Term
Polyuria
Definition
- excessive urine production
Term
Dysuria
Definition
- painful urination
Term
Haematuria
Definition

- blood in the urine

- urinary stones

- kidney disease

- glomerular infection

Term
Glycosuria
Definition

- glucose in the urine

- diabetes mellitus

- high blood glucose and ineffective glucose reabsorption

Term
Biliuria
Definition

- bile in the urine

- obstruction of bile duct

- increase amnts of bilirubin in blood excreted in urine

Term
Pyuria
Definition

- leukocytes & pus in urine

- infection in urinary tract

- infection in reproductive tract in males

Term
Albuminuria
Definition

- albumin in the urine

- renal disease

- renal complicaitons of hypertension/heart f

- heavy exercise

- fever

Term
Acetonuria
Definition

- acetone and ketones in urine

- diabetes mellitus

- starvation

Term
Nephritis
Definition
- inflammation of the kidneys
Term
Pyelonephritis
Definition
- infection involving renal pelvis
Term
Glomerulonephritis
Definition

- inflammation of the glomerulus

- ff. acute resp. infections in children

- chronic in older people assoc w/hypertension

- accompanied by proteinuria, haematuria, edema & decreased urine output

 

Term
Nephrosis
Definition

- degenerative changes in the kidney

- charac. by proteinuria & edema

- common in children

Term
Cystitis
Definition

- inflammation of the urinary bladder

- pain

- urgency to urinate

- frequent urination

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