bio 142 chapter 25 part 1

Kidneys

Filter blood to remove metabolic wastes.

Regulate fluid, electrolyte, and acid-base balance.

Ureters

Two slender, muscular tubes (about 25–30 cm long)

* Transport urine from the kidneys to the urinary bladder via peristaltic waves of smooth muscle contraction.

Urinary Bladder

Temporarily stores urine (holding up to 700–800 mL).

Contracts to expel urine during micturition (urination).

hollow, distensible, muscular sac situated in the pelvic cavity,

Urethra

single thin-walled muscular tube leading from the bladder floor to the exterior of the body.

Drains urine from the bladder to be excreted out of the body.

In males, it also serves as the passageway for semen.

What are Normal Constituents of Urine?

Creatinine

Uric Acid

Electrolytes/Ions

Urochrome

What Should NOT be Found in Urine?

Glucose

Proteins/Albumin

Red Blood Cells

White Blood Cells

Bile Pigments / Bilirubin

Ketones

Microorganisms

Muscle Type of Internal Urethral Sphincter

Smooth muscle

(Involuntary control by the autonomic nervous system).

Internal Urethral Sphincter Location in Females

at the bladder neck (where the bladder connects to the urethra).

Location in Males Internal Urethral Sphincter

bladder neck, superior to the prostate gland.

Muscle Type External Urethral Sphincter

Skeletal muscle

(Voluntary control by the somatic nervous system).

External Urethral Sphincter Location in Females

Located inferiorly, where the urethra passes through the deep perineal pouch/urogenital diaphragm

External Urethral Sphincter Location in Males

Located inferior to the prostate gland, surrounding the membranous urethra.

Mucosa of bladder wall

transitional epithelium

Submucosa of bladder wall

rregular connective tissue containing blood vessels, lymphatic vessels, and nerves.

3. Muscularis in bladder wall

Composed of three interweaving layers of smooth muscle fibers running in

longitudinal,

circular,

oblique directions.

Serosa of bladder wall

superior surface is covered by parietal peritoneum

rest is covered by loose connective tissue

function of mucosa in bladder wall

Allows the bladder to stretch and flatten out as it fills with urine without tearing.

It also acts as a barrier to prevent urine from leaking into deeper tissues.

function of submucosa in bladder wall

Supports the mucosa and connects it to the underlying muscular layer.

function of muscularis in bladder wall

Contracts forcefully during micturition (urination) to expel urine from the bladder into the urethra.

function of Serosa in bladder wall

Anchors the bladder in place within the pelvic cavity and protects the organ.

What is the muscle within the bladder called?

detrusor muscle.

In males, what gland is found inferior to the bladder?

prostate gland

In females, how does the bladder relate to the uterus?

located anterior and inferior to the uterus

as bladder fills what receptors in the walls are activated

stretch receptors

the stretch receptors send sensory impulses that travel to which muscle

detrusor muscle of the bladder causing contraction causing to empty

what do we contract to override the micturition reflex

by contracting the external urethral sphincter

Mucosa of urterus

Composed of transitional epithelium

Muscularis of ureters

two layers of smooth muscle:

inner longitudinal layer

outer circular layer

Adventitia of ureters

loose fibrous connective tissue containing blood vessels, lymphatic vessels, and nerves.

Mucosa of urterus function

Distensibility: Allows the ureter to stretch and expand as urine passes through.

Protection: Acts as a chemical barrier

Mucosa of Muscularis function

Peristalsis: Propels urine toward the bladder via active, rhythmic muscular contractions.

Mucosa of Adventitia function

Anchoring: Blends with the surrounding connective tissues to anchor the ureters securely in place along the posterior abdominal wall.

1. Where are the kidneys located?

upper abdominal area, positioned against the back body wall.

kidneys secrete what hormone

erythropoietin (EPO)

-stimulate the bone marrow to produce red blood cells

kidneys secret what enzyme

renin which plays a role in

-the renin-angiotensin-aldosterone system (RAAS). This helps regulate blood pressure.

kidneys participate in the activation of vitamin

vitamin D (converting it into calcitriol)

affects calcium and phosphate absorption in the intestines, maintaining healthy bones and teeth.

Renal Capsule

fibrous connective tissue

Protects the kidney from trauma and physical injury.

arrier against the spread of local infections into the kidney tissue

Renal Hilum

slit or indentation on the concave curved border of the kidney.

Serves as the structural "gateway" or entry/exit point for the renal artery, renal vein, nerves, lymphatic vessels, and the ureter.

Renal Cortex

light-colored, granular superficial region of the kidney located directly beneath the capsule.

Contains the filtering units of the kidney

where blood filtration begins.

Renal Column

Anchors the cortex securely

safe pathway for blood vessels

(Renal Pyramid)

Contains the collecting ducts and loops of Henle

Striated in appearance, it is responsible for concentrating urine and funneling it toward the kidney's center via the pyramid tips (papillae).

Minor Calyx

Collects urine continuously draining from a single renal pyramid.

Major Calyx:

Funnels urine from multiple minor calyces down into the renal pelvis.

Renal Pelvis

large, flat, funnel-shaped cavity located deep within the renal sinus,

as a centralized collection basin that receives all urine from the calyces and channels it directly out into the ureter.

1. What structures pass through the hilum?

VAU

Renal Vein:

Renal Artery:

Ureter

Lymphatic Vessels

Nerves