Urinary System

Question 1

1. The urinary system plays what role?
2. and is responsible for what?
3. What 4 parts are the urinary system made up of?

Answer 1

1. The urinary system plays an excretory role and is
2. responsible for eliminating urine.
3. It is made up of the kidneys, ureters, bladder and urethra.

Question 2

The body produces waste materials –

1. Name some of the waste products from the metabolic reactions that take place in the cells?
2. What from the digestive system?
3. Some essential ions, when in excess, for example

• It is essential for the health of the body that waste matter is ______ ___ _________ ________ because its build up would quickly lead to ill health.

Answer 2

The body produces waste materials –

1. Carbon dioxide, excess water, heat, and toxic wastes such as ammonia and urea are produced by the metabolic reactions that take place in the cells.
2. The digestive system does not absorb all that we ingest and so the residual is waste
3. Some essential ions, for example sodium, chloride, phosphate and nitrogen, build up to excessive levels and are no longer required.

• It is essential for the health of the body that waste matter is quickly and successfully excreted because its build up would quickly lead to ill health.

Question 3

The urinary system plays a major excretory role.

It is responsible for removing _____ _____ and unwanted _________ from the ____ and expelling them from the body as _____. It is not, however, the only body system involved in excretion…

Name three other systems that play a role in excretion…

Answer 3

The urinary system plays a major excretory role.

It is responsible for removing excess water and unwanted substances from the blood and expelling them from the body as urine. It is not, however, the only body system involved in excretion…

1. The large intestine of the digestive system prepares faeces for expulsion and eliminates it from the body.
2. The respiratory system expels carbon dioxide, heat and some moisture during exhalation, and
3. the sweat glands of the skin excrete water, heat, and small amount of salts and urea in sweat.

Question 4

Urine consists of waste material produced as a by-product of metabolism.

1. What Colour is urine normally?
2. Made up mostly of what?
3. The remainder is made up of _____ derived from ______ _________ and _______ sources.
4. These components include what (8)

Answer 4

1. Urine is a pale yellow fluid
2. which is 95% water.
3. The remaining 5% is made up of solutes derived from cellular metabolism and outside sources (e.g. drugs).
4. These components include urea, uric acid, ammonia, sodium, potassium, calcium, chloride and bicarbonate.

Question 5

The constituents that make up urine are absorbed from the blood by the __a__. The urine passes from the ___a__, down the ______ to the ___b____.

The ____b___ is a _______ ___, which temporarily stores urine. When the volume of urine in the ____b____ exceeds ___ ___ml, ______ _______ in the ___b____ trigger urination. The urine leaves the body via the _______.

Answer 5

The constituents that make up urine are absorbed from the blood by the kidneys. The urine passes from the kidneys, down the ureters to the bladder.

The bladder is a muscular sac, which temporarily stores urine. When the volume of urine in the bladder exceeds 200-400ml, stretch receptors in the bladder trigger urination. The urine leaves the body via the urethra.

Question 6

What is the physiological term for urination?

Answer 6

The act of expelling urine from the bladder is commonly called urination, but the physiological term is micturition.

Micturition is a reflex over which there is some voluntary control.

Question 7

Micturition Reflex:

• When the volume of urine in the bladder causes it to expand, the _____ _______ in the bladder wall are stimulated.
• These then transmit nerve impulses to the lower portion of the _____ ___.
• On receiving nerve impulses from the stretch receptors, the urinary control centre in the _____ spinal cord triggers the _________ _____.
• This causes the ________ muscle in the wall of the bladder to contract and the _______ ________ _________ to relax.

Voluntary control:

• The spinal cord also communicates with the ____a___ ______ to initiate the conscious desire to expel urine.
• The ___a_____ ______ permits the voluntary relaxation of the _______ _______ _________, located in the skeletal muscle that surrounds the urethra.

The combination of both the ________ _____ and _______ ______ allows urination to take place.

Answer 7

Micturition Reflex:

• When the volume of urine in the bladder causes it to expand, the stretch receptors in the bladder wall are stimulated.
• The stretch receptors then transmit nerve impulses to the lower portion of the spinal cord.
• On receiving nerve impulses from the stretch receptors, the urinary control centre in the sacral spinal cord triggers the micturition reflex. The micturition reflex causes the detrusor muscle in the wall of the bladder to contract and the internal urethral sphincter to relax.

Voluntary Control:

• The spinal cord also communicates with the cerebral cortex to initiate the conscious desire to expel urine. The cerebral cortex permits the voluntary relaxation of the external urethral sphincter, located in the skeletal muscle that surrounds the urethra.

The combination of both the micturition reflex and voluntary control allows urination to take place.

Question 8

The main function of the urinary system is to control the __________ , _______ and _________ of the blood.

The kidneys are vital to this as they ____ the blood by absorbing _____ and excessive _____. This forms urine that can be excreted from the body.

Answer 8

The main function of the urinary system is to control the composition, volume and pressure of the blood.

The kidneys are vital to this as they filter the blood by absorbing waste and excessive water. This forms urine that can be excreted from the body.

Question 9

1. Give a brief description of the kidneys
2. Where are they located?
3. Which is slightly lower?

Answer 9

1. The kidneys are bean-shaped, reddish organs.
2. They are located just above the waist at the rear of the abdomen.
3. The right kidney is located slightly lower than the left.

Question 10

1. The kidneys receive blood from ?
2. The filtered blood leaves the kidney’s via the ?

Answer 10

1. The kidneys receive their blood supply from the renal arteries.
2. The renal veins drain the filtered blood away from the kidneys.

Question 11

• Within the renal ______ is the smooth, outer region of the kidney called the __a___.
• The ___a___ surrounds the darker ___b____.
• The cone-shaped structures in the ___b___ are called renal _____c____. The __a__ and the renal ___c_____ make up the __________ part of the kidney, consisting of about 1 million microscopic ________.

Answer 11

• Within the renal capsule is the smooth, outer region of the kidney called the cortex.
• The cortex surrounds the darker medulla.
• The cone-shaped structures in the medulla are called renal pyramids. The cortex and the renal pyramids make up the functional part of the kidney, consisting of about 1 million microscopic nephrons.

Question 12

• There is a large cavity in the centre of the kidney called the renal __a___.
• The renal __a__ has cup-shaped extensions called ___b___.
• Each __c__ receives urine from the collecting ducts of one renal _______.
• The urine then drains from the __c__ into the renal ___a__.
• The ________ action of the renal ___a__ encourages the urine to drain into the ______.

Answer 12

• There is a large cavity in the centre of the kidney called the renal pelvis.
• The renal pelvis has cup-shaped extensions called calyces.
• Each calyx receives urine from the collecting ducts of one renal pyramid.
• The urine then drains from the calyx into the renal pelvis.
• The peristaltic action of the renal pelvis encourages the urine to drain into the ureter.

Question 13

In order for the kidneys to perform their vital blood filtration processes, they have a vast capillary network. Situated within this network of blood vessels are numerous microscopic tubules called ____a____.

____a____ are the ________ units of the kidney. They extend from the renal _______, through the ______ and _______, to the cup-shaped extensions of the renal _____, absorbing _______ and _________ substances from the blood.

Answer 13

In order for the kidneys to perform their vital blood filtration processes, they have a vast capillary network. Situated within this network of blood vessels are numerous microscopic tubules called nephrons.

Nephrons are the functional units of the kidney. They extend from the renal capsule, through the cortex and medulla, to the cup-shaped extensions of the renal pelvis, absorbing excessive and unwanted substances from the blood.

Question 14

• How long are Nephrons?
• The cup-shaped Bowmans capsule encloses a small group of capillaries called the what?
• It is across the walls of the _________ __________ that water and waste are filtered from the blood.
• The blood pressure is very high in the glomerus because the _______ _________ is smaller in diameter than the ________ ________, creating a high resistance to blood flow.
• This high pressure ________ _________ of substances in the blood through the capillary walls and into the Bowman’s capsule.

Answer 14

• Nephrons are 2-4cm long.
• The cup-shaped Bowman’s capsule encloses a small group of capillaries called the glomerus.
• It is across the walls of the Bowman’s capsule that water and waste are filtered from the blood.
• The blood pressure is very high in the glomerus because the efferent arteriole is smaller in diameter than the afferent arteriole, creating a high resistance to blood flow.
• This high pressure increases filtration of substances in the blood through the capillary walls and into the Bowman’s capsule.