Urinary system in Humans

Question 1

What is the structure of the urinary sytem?

Answer 1

the urinary system consits of
Two kidneys
Two ureters
Bladder
urethra

Question 2

What are the two types of blood vessels in the urninary system?

Answer 2

• Renal artieries
• Renal veins

Question 3

Explain the urninary sytem in humans.

Answer 3

• The kidneys receive Oxygenated blood (rich in metabolic waste products) from the renal artiers
• Deoxygenated blood (purified of metabolic waste products) is transported away from the kidneys via the renal vein
• The ureter extends from each kidney and opens seperatly into the bladder
• The bladder is a thin walled musclular sac in which urine is temporarily stored
• The urethra transports the urine from the bladder to the exterior
• A sphincter muscle controls the flow of urine to the urethra

Question 4

What are the internal parts of the kidney?

Answer 4

• The kidney is surrounded by a connective tissue membrane, the renal capsule, for protection
• Directly under the renal capsule is a reddish brown region known as the cortex.
• The inner region of the kidney, the mudulla, is lighter in colour and contains tubes which are arranged in groups
• Each group of tubes forms a** pyrimid**, witth the broad base facing the cortex
• The apex of each pyrimid is known as the renal papilla
• The tubes in each renal papilla open into a common **renal calyx **

Question 5

What microscopic structure is the kidney made of?

Answer 5

The nephron

Question 6

What is the two main parts of the nephron

Answer 6

• Malpighian body
• renal tubule

Question 7

What does the Malpighian body consist of?

Answer 7

• The Bowman’s capsule
• Glomerulus
• afferent atreriole
• efferent arteriole

Question 8

The Bowman’s capsule consists of specialised cells, the podocytes. What are podocytes?

Answer 8

Podocytes are cells with projections between which small openings, the filtration slits occur

Question 9

What is the Renal tubule?

Answer 9

The Renal tuble is a long convoluted tubule that is situated partially in the cortex and partially in the medulla

Question 10

What are the 3 parts the Renal tubule consist of?

Answer 10

• The proximal convaluted tubule
• the loop of henle
• the distal convaluted tubule

Question 11

Where is the Proximal convaluted tubule situated?

Answer 11

The Proximal convaluted tubule follows directly afer the Bowman’s capsule and is situated in the cortex

Question 12

What is the Proximal tubule’s appearince in the renal tubule?

Answer 12

The Renal tubule is at its widest in the proximal tubule and is lined with a single layer of cuboidal epithelium

Question 13

What does the loop of henle consist of?

Answer 13

• a decending limb which extends down into the medulla and forms a hairpin
• an ascending limb which extends up into the cortex

Question 14

Where is the loop of henle situated?

Answer 14

the medulla

Question 15

Where is the distal convaluted tubule situated?

Answer 15

The distal convaluted tubule is situateed in the cortex like the proximal tubule and is also line with a single layer of cuboidal epithelium

Question 16

to where does the distal convaluted tubule open up to along with a number of other distal convaluted tubules?

Answer 16

the collecting duct

Question 17

What is a few collecting ducts converging called?

Answer 17

a few collecting ducts converg and form the ducts of bellini

Question 18

Explain the blood supply of the kidney.

Answer 18

• Each kidney is supplied with the blood from a renal artery
• which carries oxygenated blood rich in metabolic waste products to the kidney
• The renal artery enters the kidney at the hilum
• The artery branches into smaller arteries that exstends between the pyrimids in the direction of the cortex
• they then branch further until they form the smallest branches in the cortex called affrent arterioles
• one affrent arteriole extends to each bowmans’s capsule
• The affrent arteriole devides to from a capillary network (the Glomerulus) which fits inside the cup-shaped hollow of the bowman’s capsule
• the blood capillaries then merge and form an** efferent arteriole** which transports blood away from the bowman’s capsule
• the efferent arteriole branches again and forms a second network of blood vessels (the peritubular capillary network) which surrounds the renal tubule
• the renal cappilaries combine to form venules and larger veins that eventually form the renal vein which takes deoxygenated blood without the waste products and delivers it to the heart

Question 19

What doe the ducts of bellini form?

Answer 19

the ducts of bellini form the pyrimids that open into the renal calyx of the renal pelvis

Question 20

What are the 3 fuctions of the kidney?

Answer 20

• Glomerular filtration (Ultra filtration)
• Tubular reabsorption
• tubular excretion

Question 21

Shortly explain the glomerular filtration process

Answer 21

• occurs in the Malpighian bodies in the cortex
• the glomerulas is under high pressure because the afferent arteriole is larger than efferent
• the thin epetheliem with pores in the blood cappilaries and the podocyte layer with filtration slits in the bowman’s capsule, together form an ultrafine filter
• Blood cells, plasma proteins are too big to filter and remain behind
• part of the blood that moves through the filtrations is known as Glomerulas filtrate and has usefull stuff and waste products

Question 22

What are the useful substances in the filtrate?

Answer 22

• water
• amino acids
• glucose
• vitamins
• mineral salts

Question 23

what are the waste products in the filtrate?

Answer 23

• urea
• uric acid
• creatinine

Question 24

What is the filtration process promoted by?

Answer 24

• high blood pressure in the glomerulus
• a large filtration surface
• the permeability of the glomerular membrane

Question 25

What are some adaptions of the Malpighian body for filtration?

Answer 25

* afferent artieriole is wider than efferent causeing high blood pressure * capillarie network of glomerulus has a large surface area * Bowman's capsule is cup-shaped which provides a large surface * Endothelial layer of the Glomerulus and podocytre layer of bowman's capusule form an ultrafine filter * endothelial layer has pores * podocytre layer has filtration slits

Question 26

Explain what tubular reabsorption is.

Answer 26

It is the process where usefull substances must now be reabsorbed and returned to the blood stream. th filtrater leaves the Bowman's capsule and enters the proximal convoluted tubule.

Question 27

What are the adaptions for the proximal convaluted tubule for reabsorption?

Answer 27

* The tubule is long and convaluted, which enlarges the surface for maximal reabsorption * the peritubular capilary network surrounds the renal tububle so that reabsorbed substances can easily move into the bloodstream * The cuboidal epithelium cells, which line the tubule, have many mitochondria which provide energy meaning this process is an active transport mechanism * The cubodial epithelial cells have finger-like projections which increase the absorption surface

Question 28

Explain Tubular excretion.

Answer 28

During this process substances are secreted from the blood in the surrounding peritubular capillaries throught the epitheluim of the renal tubule and added to the filtrate, this prosecc occurs in the proximal and distal convaluted tubules.

Question 29

How is urine formed?

Answer 29

* The filtrate flows into the collecting ducts and is now called urine * urine flows throught the ureter into the bladder * urine is temporarily stored in the bladder * urine is transported from the bladder to the exterior by the urethra

Question 30

What is the compasition of urine?

Answer 30

* water * inorganic salts * metabolic wastes * foreign substances