Urinary system Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Intro

A

Bladder can hold 2 cups of urine comfortable and 1L when full

  • during 24 hours, kidneys process 150-180L of water and solutes
  • avg adult voids 1-2 L a day
  • regulates content of blood plasma to maintain homeostasis of internal fluid environment
  • not related to waste elimination are
    1. Maintaining blood volume
    2. Maintiaing normal blood pressure
    3. Maintaining normal blood composition
    4. Maintaining normal body and blood pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Anatomy of urinary system

A

Kidneys, ureters, urniary bladder, urethra

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

Kidneys

A

Size of soap with medial indentation (hilum)

  • left kidney is larger than right
  • right kidney lies lower
  • sandwich ther vertebral column between T12 and L3 (posterior aspect of abdomen = retroperitoneal
  • fat surrounds each kidney
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

External anatomy of kidney

A

Renal hilum: Blood vessels and other structures enter or leave the kidney

  • surroundig kidney:
    1. Superficial = renal fascia
    2. Middle = adipose capsule
    3. Deep = renal capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Internal structures

A
  • renal cortex
  • renal medulla
  • renal pyramids
  • renal columns
  • calyx
  • renal pelvis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Renal cortex

A

Outer region

  • superficial light red region
  • smooth-textured area
  • extends from the renal capsule to the bases of the renal pyramids and into the spaces between them
  • the portions that extend between the renal pyramids are called renal columns
  • divided into the outer cortical zone and the inner juxtamedullary zone
  • together with renal pyramids constitute the parenchyma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Renal medulla

A

Inner region

  1. renal pyramids: several cone shaped structure of the renal medulla
    - base = wide, apex = renal papilla which points to hilum
    - contains nephrons
    - each renal papilla ends in a cup like structure called a calyx
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nephron

A

Functional unit of the kidney (filters)
- filtrate drains into papillary ducts, which extend through renal papillar of the pyramids. Ducts drain into cuplike structures called minor and majorly calyces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Renal pelvis

A

Received urine from the major calyces

- narrows as it exits a kidney to become a ureter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Blood vessels of kidneys

A

Highly vascularized

  • 1200mL/min of blood flows through them
  • receive 20-25% of resting cardiac output via right and left renal arteries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Renal corpuscle

A

First part of the nephron

  • glomerus (capillaries): capillary network
  • bowman capsule: (glomerular) double walled epitheial cup that surrounds the globular capillaries
  • fluid from the blood filters out of the glomerus and into the glomerular capsule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Renal tubule

A

In nephron

  • Proximal convoluted tube
  • henle loop (nephron loop)
  • distal convoluted tubule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Glomerular (bowman’s) capsule

A
  • cup shaped mouth of nephron
  • formed by tow layers of epithelial cells with a space between them
  • plasma (fluids, waste products, an delectrolyes) passes through the glomerular capillaries and enters this space to be processed into urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Glomerulus

A

A network of fine capillaries in bowman’s Caplsule

  • glomerular capillaries have thin, membranous walls
  • the endothelium has many pores present which are important for filtration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Renal tubule

A
  • collecting duct: joining the renal tubules of several nephrons. All collectiong ducts of one renal pyramid converge at a renal papilla. Openings at the renal papilla release urine into one of the minor calyces
    1. Proximal convoluted tubule (PCT): first part of the renal tubule, attached to glomerular capsule
    2. Nephron loos (loop of henle): segment of renal tubule beyond the PCT. important in the production of highly concentrated or very dilute urine
    3. Distal convoluted tubule (DCT): convoluted tubule beyond the nephron loop. Extends into th renal medulla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ureter

A
  • 2 tubules that convey fine from the kidneys to the bladder
  • about 28-34 cm in length
  • begin around L1
  • ureters enter the bladder at an oblique angle which allows for them to close and act as valves when the bladder is full
17
Q

Urinary bladder

A

A muscular, collapsible lumen located directly posterior to the pubic symphysis

  • the wall of the bladder is made mostly of smooth muscle
    1. Reservoir for urine
    2. Expels urine from the body via the urethra
18
Q

Urethra

A

Small mucous membrane-lined tube, extending from the floor of the bladder (trigone) to the exterior of the body

19
Q

Female urethra

A

Lies posterior to symphysis pubis and anterior to the vagina (3cm long)

20
Q

Male urethra

A

Is passes through the prostate gland where it is joined by two ejactulatory ducts

  • from the prostate, it extends to the base of the penis
  • travels centrally to the tip of the penis (20cm long)
21
Q

Physiology of urinary system

A
  1. Kidneys: Process blood to form urine and maintain homeostasis
  2. Nephron forms urine
    - filtration
    - tubular reabsorption
    - tubular secretion
22
Q

Función of kidneys

A
  • most imporant organ for maintaining fluid balance
  • filter and excrete waste, solutes, and toxins
  • absorb water, electrolytes, and buffers
  • recycle necessary elements and maintain normal blood volume, BP, and pH levels
  • synthesize hormones: erythropoietin (which stimulates RBC formation) and calcitriol (active form of vit D)
  • simplicity of the kidney’s blood supply makes transplantation relatively easy
23
Q

Glomerular filtration

A
  • first step in processing blood to form urine occurs in renal corpuscles
  • plasma moves across the wall of glomerular capillaries
  • filtration occurs as result of a pressure gradient
24
Q

Tubular reabsorption

A
  • second step in urine formation occurs in proximal tubules (PCT)
  • movement of molecules out of the segments of tubule and into the blood
  • reabsorption in proximal tubule: 99% of the filtered water and solutes are recovered by the blood, leaving only a small volume of fluid in tubule to move on the the loop of henle
25
Q

Tubular secretion

A
  • third step in urine formation
  • filtered fluid flows through renal tubules and collecting ducts
  • renal tubule and duct cells secrete other materials into fluid (waste, drugs, excessions)
  • occurs in the distal tubule and collecting duct
  • prime componentes that are not reabsorbed: urea, creatinine, uric acid
26
Q

Micturition

A

Mechanisms for voiding
- bladder has two sphincters: internal (involuntary) and external (voluntary)
- internal urethral orifice: opening into urethra. Lies in the anterior corner of the trigone
- wall of the bladder: mucosa (deep layer that contains rugae), muscularis (smooth muscle, detrusor muscle), and adventitia (superior tissue continuous with ureters)
-

27
Q

Detrusro mm

A
  • smooth contracts reflexively with increase filling of bladder and volume exceeds 200-400mL
  • pressure rises causing relation of interna sphincter
  • voluntary relaxation o fecternal sphincter mm
  • urine is forced out of the bladder and through the urethra
28
Q

Regulation of urine vol

A

Antidieretic hormone and aldosterone work in concert to influence water and sodium reabsorption by the distal tubules and collecting ducts

  • as water is reabsorbed, total volume of urine is reduced
  • ADH and aldosterone reduce water loss by the body
  • ADH secreted by posterior pituitary
  • AHD stimulates water reabsorption by the distal tubule/collecting duct
  • aldosterone, secreted by adrenal cortex
  • aldosterone stimulates sodium reabsorption by the distal tubule/collecting duct
  • +AHD and aldosterone release = decrease urine output and increase blood volume
  • water and sodium reabsorbed into blood
  • -ADH and aldosterone release = increase urine output and decrease blood volume
  • water and sodium secreted in tubules
29
Q

Urine composition

A

Approx 95% water with several substances dissolved in it

- nitrogenous waste - electrolytes - toxins = pigments - hormones - abnormal constituents

30
Q

Summary

A

Homeostasis of water and electrolytes in body fluids relies on proper functioning of the kidneys
- nephrons process blood to adjust its content to maintain a relatively contant internal environment