Term
| List the functions of the urinary system. |
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Definition
- To regulate the chemical composition and volume
of the body fluids – osmoregulation
- To remove nitrogenous waste products and excess
water from the body – excretion
■ To act as an endocrine gland by the secretion of
the hormone erythropoietin |
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Term
| Which kidney is located more cranially and why? |
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Definition
The
right kidney lies slightly cranial to the left because
the stomach has evolved to lie on the left side of the
abdomen, pushing the left kidney out of position. |
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Term
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Definition
a cup-shaped structure
enclosing a network of blood capillaries called the
glomerulus (Fig. 10.6). The capsule may also be
known as Bowman’s capsule. The capsule and the
glomerulus form the renal corpuscle. The basement
membrane of the inner surface of the capsule,
which is in close contact with the endothelium of the glomerular capillaries, is lined by podocyte
cells between which are tiny pores (Fig 10.6).
These pores are of such a size that they will allow
the passage of fluid and small molecules, but restrict
the passage of larger molecules. The outer surface of
Bowman’s capsule is continuous with the
epithelium of the proximal convoluted tubule. Fluid
filtered by the capsule drains into the space between
the two layers and continues into the next part of
the nephron |
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Term
| Proximal convoluted tubule |
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Definition
a long twisted tube
leading from the neck of the capsule and lying in
the renal cortex (Fig. 10.5). The tubules are lined
in simple cuboidal or columnar epithelium. The side
of the epithelium directed towards the lumen of
the tubule is lined by fine microvilli forming a
‘brush border’. This increases the surface area for
the reabsorption of water and electrolytes. |
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Term
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Definition
a U-shaped part of the tube leading
from the proximal convoluted tubule and dipping
down into the renal medulla. The tubule is lined in
simple squamous epithelium which is thicker in the
ascending loop than in the descending loop |
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Term
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Definition
a short but less twisted
part of the tube than the proximal convoluted
tubule. It lies in the renal cortex and is lined in
cuboidal epithelium without a brush border. |
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Term
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Definition
each duct receives urine from
several nephrons and conducts it through the
pyramids into the renal pelvis. The ducts are lined
in columnar epithelium. |
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Term
The physiological processes occurring in the renal
nephrons are |
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Definition
Osmosis – passage of water from a weaker to a stronger
solution across a semi-permeable membrane
Diffusion – passage of a substance from a high
concentration to a low concentration
Reabsorption – passage of a substance from the lumen of
the renal tubules into the renal capillaries and so back into
the circulation; this is an active process and requires energy
Secretion – passage of chemical substances from the renal
capillaries into the lumen of the tubules and out of the body
in the urine; this is an active process and requires energy |
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Term
|
Definition
passage of water from a weaker to a stronger
solution across a semi-permeable membrane |
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Term
|
Definition
passage of a substance from a high
concentration to a low concentration |
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Term
|
Definition
passage of a substance from the lumen of
the renal tubules into the renal capillaries and so back into
the circulation; this is an active process and requires energy |
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Term
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Definition
passage of chemical substances from the renal
capillaries into the lumen of the tubules and out of the body
in the urine; this is an active process and requires energy. |
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Term
| 8. Approximately how many nephrons does a kidney contain? |
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Definition
Each kidney contains about a 200,000 (cat) to 1 million (humans, sheep, pigs) nephrons
which are closely packed together. They are responsible
for the filtration of blood and the production of urine.
Each nephron is a long tubule divided into several
parts:
med size dog ~ 700,000
cattle ~ 4,000,000 |
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Term
| Name the 5 main parts of a nephron in order of flow of filtrate |
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Definition
- Glomerular capsule/glomerulus
- proximal convoluted tubule
- loop of Henle
- distal convoluted tubule
- collecting duct |
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Term
| 6. What is the functional unit of the kidney? |
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Definition
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Term
| Advantages/Disadvantages of collection via Spontaneous micturition |
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Definition
Advantages
No risk (eg, trauma, bacterial infection) to animal. Avoids iatrogenic hematuria.
Disadvantages
May contain debris (eg, bacteria, exudate) from lower urinary and genital tract. If bacterial growth appears on urine culture, must differentiate between urethral contamination |
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