The Kidney

What is the function of the kidneys?

Maintnence of homeostasis. Disposal of waste, osmoregulation, regulation of blood pressure and volume, regulation of blood pH, producing hormones

Approximately how much can the bladder hold?

700-1000 mls

What anatomical feature of the bladder polices excretion?

Urinary sphincter

Kidneys

• Located in the posterior wall of the abdominal cavity

• Around level of twelth rib

• Left kindey is slightly higher

Where do the kidneys recieve their blood supply from

directly from aorta via renal arteries. Returned to inferior vena cava via renal veins

Why do the kidneys have such a high blood flow?

They are responsible for filtering the blood

What covers the kidneys?

A tough outer layer called the capsule. It prevents the kidneys from changing shape, etc

What are the two regions of the kidneys?

Outer part → Cortex

Inner → Medulla

Where does urine production take place?

Medulla

What are the cortex and medulla made of?

Nephrons

What are the nephrons?

They are the functional units of the kidney. They are made of two parts, the renal corpuscle and a renal tube. They are responsible for the ultrafiltration of blood (corpuscle) and reabsorption and exretion (renal tube)

What is the capillary bed in the corpuscle called?

Glomerulus

What is the area of the renal tube that encases the glomerulus called?

Bowman's capsule

What is unusual about the blood supply to the renal corpuscule?

The blood vessel coming out of the glomerulus appears to be an artery, not a vein. That’s because it IS an arteriole that supplies blood to the nephron.

Why is it significant that the capillary network is both supplied and drained by an arteriole in the renal corpuscle?

Because arteries are better to control since they have muscle tissue. Helps regulate blood pressure

What is the bowmen’s capsule made of?

double walled cup of epithelial cells

What type of epithelium comprises the visceral layer of the renal corpuscule given its function for filtration

simple squamous epithelium

What is the first step of urine production?

Glomuler filtration. Water and most solutes in blood plasma pass through glomerular capillaries to glomerular capsule

Approximately how many litres are filtered a day?

180

How many litres of urine are excreted in a healthy individual per day?

2 litres

What are the components of the renal tube?

Proximal convoluted tuble

Loop of henle

Distal convoluted tuble

Proximal Convulated Tuble

Largly responsible for the reabsorption of glucose, sodium, and other solutes

Loop of Henle

Counter current multiplyer that plays a key role in the concentration of urine by creating an osmotic gradient in the renal medulla. This reglation of urine concentration is important for regulating blood pressure. Descending limb is highly pereable to water and the ascending limb is permeable to solutes. Collecting ducts can control how permeable they are to either water or solutes.

Distal convoluted tuble

reabrobs water from filtrate

How does the anti-diretic hormone control the permeabilty of the collecting ducts?

It stimulates thhe insertion of aquaporins into the collecting duct membranes, increasing water reabsorption. The more water is reabrorbed, the more concentrated the urine.

Vasopressin is another name for ADH. What is another function of ADH based on that name?

It promotes vasoconstriction, which increases blood pressure.

How does the Sympathetic NS act of the kidneys?

• Can lower sodium and water exretion

• Can increase angiotensinII production, leading to increased blood pressure and reduced urine output.

How does the Parathyroid hormone act on the kidneys?

Increases the reabrorption of calcium in the distol convulated tuble

How do the natriuretic peptides act of the kidneys?

• Atrial natriuretic peptide (ANP) → secreted by atrial myocytes in response to distension

• Brain natriuretic peptide (BNP)→ mainly secreted by ventricles in response to stretch

• C-type natriuretic peptide (CNP) → formed in brain and vascular epithelium.

They promote sodium excretion and reduce blood volume, leading to lower blood pressure. “Natriuretic” refers to sodium.