Urinary System

Question 1

Kidney

Answer 1

Either one of a pair of organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration and filter the blood of metabolic wastes, which are then excreted as urine.

Question 2

Urine

Answer 2

The waste product secreted by the kidneys that in mammals is a yellow to amber coloured, slightly acidic fluid discharged from the body through the urethra.

Question 3

Bladder

Answer 3

A distensible membranous sac that serves as a receptacle for fluid or gas.

Question 4

Urea

Answer 4

A water soluble compound that s the major nitrogenous end product of protein metabolism and is the chief nitrogenous component of the urine.

Question 5

Sodium chloride

Answer 5

A colourless or white crystalline compound, the major cation of the extracellular fluid, constituting 90-95% of all cations in the blood plasma and interstitial fluid, thus determining the osmolality of the extracellular fluid.

Question 6

Nutrients

Answer 6

A food or biochemical substance used by the body that must be supplied in adequate amounts from foods comsumed. There are 6 classes of nutrients; water, proteins, carbohydrates, fats, minerals and vitamins.

Question 7

Capillary bed

Answer 7

Capillaries of a tissue, area or organ considered collectively and their volume capacity.

Question 8

Vasa recta

Answer 8

Straight vessels into which the efferent arteriole of the juxtamedullary glomeruli breaks up, they form a leash of vessels that run through the renal medulla towards the apex of each pyramid.

Question 9

Peritubular capillaries

Answer 9

Blood capillary beds surrounding the renal tubules of nephrons.

Question 10

Renal artey

Answer 10

Branches from the abdominal aorta at L1 vertebral level, the second and largest pair of lateral visceral branches. Supplies oxygenated blood to the kidneys.

Question 11

Osmolarity

Answer 11

The concentration of a solution in terms of osmoles of solutes per liter of solution

Question 12

Filtration

Answer 12

Passage through a filter or other material that prevents passage of certain molecules, particles or substances.

Question 13

Renal veins

Answer 13

Large veins formed at the renal hilus, opening into the inferior vena cava at the level of the 2nd lumbar vertebra. The left renal vein receives the left suprarenal vein and the left gonadal vein.

Question 14

Ions

Answer 14

An atom or group of atoms that has acquired a net electric charge by gaining or losing one or more electrons.

Question 15

Filtrate

Answer 15

A liquid or gas that has passed through a filter.

Question 16

Nephron

Answer 16

The functional excretory unit of the vertebrate kidney that regulates the amount of water in the body and filters wastes from the blood to produce urine.

Question 17

Glucose

Answer 17

A monosaccharide sugar that is used by living things to obtain energy through the process of aerobic respiration within cells.

Question 18

Renal cortex

Answer 18

The granular outer layer of the kidney, composed mainly of glomeruli and convoluted tubules, extending in columns between the pyramids that consitute the renal medulla.

Question 19

Renal medulla

Answer 19

The inner part of the substance of the kidney, composing chiefly of collecting tubules and organized into a group of structures called the renal pyramids.

Question 20

Renal calyx

Answer 20

Chambers of the kidney through which urine passes, from the apex of the renal pyramids though the renal papilla to the minor calyx. Two or three converge to form a major calyx, through which urine passes to the renal pelvis and into the urether.

Question 21

Renal pelvis

Answer 21

The funnel like dilated proximal part of the ureter in the kidney. The point of convergence of 2 or 3 major calyces.

Question 22

Urethra

Answer 22

The canal through which urine is discharged from the bladder.

Question 23

Ureter

Answer 23

Tubes made of smooth muscle fibers that propel urine from the kidneys to the urinary bladder.

Question 24

Hilum

Answer 24

Part of an organ where structures such as blood vessels an nerves enter.

Question 25

Homeostasis

Answer 25

A state of equilibrium, an organism or cell being maintained by self regulating processes.

Question 26

pH

Answer 26

A measure of the degree to which a solution is acidic or alkaline. The more acidic a solution, the greater the hydrogen ion concentration and the lower the pH.

Question 27

Blood pressure

Answer 27

The pressure of the blood against the walls of any blood vessel, usually within the arteries. Determined by the pumping action of the heart, the resistance to the flow of blood in the arterioles, elasticity of the walls of the main arteries, blood volume, extracellular fluid volume and blood's viscosity or thickness.

Question 28

Glomerular filtration rate

Answer 28

An expression of the quantity of glomerular filtrate formed each minute in the nephrons of both kidneys, calculated by measuring the clearance of specific substances e.g inulin or creatinine.

Question 29

Arteriole

Answer 29

A minute arterial branch.

Question 30

Afferent arteriole

Answer 30

Any arteriole that connects the terminal branch of an artery with a capillary.

Question 31

Efferent arteriole

Answer 31

Blood vessels in the urinary tract that form a convergence of the capillaries of the glomerulus. They play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure.

Question 32

Glomerulus

Answer 32

Globular structures of entwined vessels, fibers or neurons.

Question 33

Bowman's capsule

Answer 33

A membranous, double walled capsule surrounding a glomerulus of a nephron.

Question 34

Bowman's space

Answer 34

The space within Bowman's capsule surrounding the glomerulus. This is where the glomerular plasma filtrate collects as it leaves the capillaries through the filtration membrane.

Question 35

Amino acids

Answer 35

The basic constituent of protein. Body protein breaks down into 20 different amino acids, some can be synthesized by the body, others, known as essential amino acids, must be obtained from protein in the diet. Amino acids group together to form peptides, linked by peptide bonds.

Question 36

Endothelial cell

Answer 36

One of the simple squamous cells forming the lining of blood and lymph vessels and the inner layer of the endocardium.

Question 37

Fenestrated

Answer 37

Having fenestrae or window like openings.

Question 38

Basement membrane

Answer 38

A sheet os amorphous extracellular material upon which the basal surfaces of epithelial cells rest, it is also associated with muscle cells, Schwann cells, fat cells and capillaries, interposed between the cellular elements and the underlying connnective tissue. It comprises of 2 layers, basal lamina and reticular lamina and is composed of Type IV collagen unique to basement membranes, laminin, fibronectin and haparan sulpfate proteoglycans.

Question 39

Semipermeable

Answer 39

Permitting passage only of certain molecules.

Question 40

Protein

Answer 40

Macromolecules consisting of long sequences of amino acids in peptide linkage.

Question 41

Podocytes

Answer 41

The modified epithelial cell of the visceral layer of glomerular capsule in the renal corpuscle, attached to the outer surface of the glomerular capillary basement membrane by cytoplasmic foot processes believed to play a role in the ultrafiltration of blood.

Question 42

Renal tubule

Answer 42

The mnute canals composing the substance of the kidney and secreting, collecting and conducting the urine, in the glomerulus they have a basement membrane and epithelial lining.

Question 43

Epithelial cell

Answer 43

One of the many varieties of cells that form epithelium. Epithelial cells are closely packed and take on polyhedral shapes, from tall, squat or flat. They adhere strongly to one another and the basal surface sticks firmly to a thin extracellular film of fibrils called basal lamina.

Question 44

Renal artery stenosis

Answer 44

A blockage or narrowing of the major arteries that supply blood to the kidneys.

Question 45

Proximal convoluted tubule

Answer 45

The convoluted portion of the vertebrate nephron lying between Bowman's capsule and the loop of Henle. It functions in the resorption of sugar, sodium, chloride ions and water.

Question 46

Loop of Henle

Answer 46

The U shaped portion of a renal tubule formed by a descending and an ascending tubule.

Question 47

Descending limb

Answer 47

The portion of the renal tubule constituting the first part of the Loop of Henle. Low permeability to sodium and chloride ions. Moderate permeability to urea. High permeability to water, readily reabsorbed by osmosis.

Question 48

Ascending limb

Answer 48

Part of the renal tubule after the sharp bend of the loop of Henle, divided into a thin and thick portion. The thin portion is impermeable to water and ions, except sodium and chloride which cross by diffusion. The thick portion is impermeable to water, but sodium, potassium and chloride ions are reabsorbed by active transport. The thick ascending limb is the site of action of loop diuretics such as furosemide, that block the potassium, sodium and chloride co-transporter.

Question 49

Chloride

Answer 49

Elemental chlorine that gained an electron, essential electrolyte found in all body fluids and is critical for maintaining pH, regulating fluids and electrolyte balance and digesting food.

Question 50

Potassium

Answer 50

A chemical element that in combination with other minerals in the body, forms alkaline salts that are important in maintenance of the acid base and water balance in the body. All body cells, especially muscle tissue, require a high content of potassium.

Question 51

Counter current mechanism system

Answer 51

A mechanism that expends energy to create a concentration gradient. For example, the countercurrent flow within the descending and ascending limbs of the loop of Henle increased or multiplies the osmotic gradient between tubular fluid and interstitial space.

Question 52

Active transport

Answer 52

The movement of a chemical substance through a gradient of concentration or electrical potential in the direction opposite to normal diffusion, requiring the expenditure of energy.

Question 53

Passive absorption

Answer 53

The process of taking in gases, liquids, light or heat.

Question 54

Interstitium

Answer 54

A small area, space or gap in the substance of an organ or tissue.

Question 55

Distal convoluted tubule

Answer 55

The portion of a kidney nephron between the loop of Henle and the collecting duct system.

Question 56

Juxtaglomerular apparatus

Answer 56

A collective term for the juxtaglomerular cells of the afferent arteriole and macular densa in the distal convoluted tubule of a nephron. This structure initiates the renin-angiotensin mechanism to elevate blood pressure and increase sodium retention.

Question 57

Juxtaglomerular cells

Answer 57

Modified smooth muscle cells in the wall of the afferent glomerular arteriole.

Question 58

Macula densa

Answer 58

A zone of heavily nucleated cells in the distal renal tubule that feed information to the juxtaglomerular cells.

Question 59

Collecting tubule

Answer 59

One of the small ducts that receive urine from several renal tubules, which join together to provide a passage for the urine t the papillary ducts that open into the pelvis of the kidney.

Question 60

Peritubular capillaries

Answer 60

Blood capillary beds surrounding the renal tubules of nephrons.

Question 61

Micturition

Answer 61

The discharge of urine from the bladder. Urins from the kidneys is passed in sprts every few seconds along the ureters to the bladder, where it collects and later is passed to the outside via the urethra.

Question 62

Transitional epithelium

Answer 62

A type of epithelium characteristically found lining hollow organs, such as the urinary bladder, that are subject to great mechanical change due to contraction and distention.

Question 63

Internal urethral sphincter

Answer 63

The complete collar of smooth muscle cells of the neck of the urinary bladder that extends distally to surround the preprostatic portion of the male urethra.

Question 64

Membranous urethra

Answer 64

The shortest and narrowest portion of the male urethra, extending from the prostate to the beginning of the urethra in the corpus spongiosum, just beyond the bulb

Question 65

External sphincter

Answer 65

A muscle of the urethra located in the deep perineal pouch, at the bladder's distal end. It is a secondary sphincter to control the flow of urine through the urethra.

Question 66

Prostatic urethra

Answer 66

The prostatic part of the male urethra that traverses the prostate, it includes the seminal colliculus and the ejaculatory and prostatic ducts that open into it.

Question 67

Spongy urethra

Answer 67

The portion of the male urethra which traverses the corpus spongiosum.

Question 68

Urinary tract infection

Answer 68

Infection in the urinary tract, types are names for the part of the tract involved such as urethritis, cystitis, ureteritis, pyelonephritis and glomerulonephritis. It is more common in women due to the relative shortness of the urethra. Men over 50 are more susceptible due to prostate enlargement and urinary stasis.

Question 69

Excrete

Answer 69

To separate and discharge waste matter from the blood, tissues or organs.

Question 70

Waste

Answer 70

Material that is unfit for further use within the organism.

Question 71

Hormone

Answer 71

A chemical transmitter substance produced by cells of the body and transported by the bloodstream to the cells and organs on which it has a specific regulatory effect.

Question 72

Hypertonic

Answer 72

Having an osmotic pressure greater than that of the solution with which it is compared.

Question 73

Collecting duct

Answer 73

The part of the renal tubule in a kidney in which water absorption takes place under the control of antidiuretic hormone, producing a urine of variable concentration depending on overall water levels in the body.

Question 74

Antidiuretic hormone

Answer 74

Also known as vasopressin. A hormone secreted by cells of the hypothalamic nuclei and stored in the posterior pituitary for release as necessary. it stimulates contraction of the muscular tissues of the capillaries and arterioles, raising the blood pressure and increasing peristalsis, exerts some influence on the uterus and influences resorption of water by the kidney tubules, resulting in concentration of urine. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

Question 75

Vasopressin

Answer 75

Also known as antidiuretic hormone. A hormone secreted by cells of the hypothalamic nuclei and stored in the posterior pituitary for release as necessary. it stimulates contraction of the muscular tissues of the capillaries and arterioles, raising the blood pressure and increasing peristalsis, exerts some influence on the uterus and influences resorption of water by the kidney tubules, resulting in concentration of urine. Its rate of secretion is regulated chiefly by the osmolarity of the plasma.

Question 76

Brush border

Answer 76

A specialization of the free surface of a cell, consisting of minute cylindrical processes, or microvilli, that greatly increase the surface area.

Question 77

Lumen

Answer 77

The cavity or channel within a tube or tubular organ, as a blood vessel or the intestine.

Question 78

Apical

Answer 78

Pertaining to an apex

Question 79

ATP

Answer 79

A nucleotide composed of adenosine and 3 phosphate groups and releases energy when hydrolyzed to ADP. It is present in all cells ,where it is used to store and transport energy needed to biochemical reactions.

Question 80

Sodium-potassium pump

Answer 80

A mechanism of active transport that moves potassium ions into and sodium ions out of a cell.

Question 81

Symporter

Answer 81

A membrane protein that carries 2 different ions or molecules in the same direction through the membrane.

Question 82

Cotransporter

Answer 82

A subcategory of membrane transport proteins that couple the favourable movement of one molecule with its concentration gradient and unfavourable movement of another molecule against its concentration gradient. This includes antiporters and symporters.