D3.3 HL only

Question 1

nitrogen containing compounds

Answer 1

essential building blocks of living organisms. Amino acids, nucleic acids, and nucleobases are key biological nitrogen compounds

Question 2

nitrogenous waste

Answer 2

any waste product that is nitrogen-based.Nitrogenous wastesare formed when proteins are broken down into amino acids for energy. Ammonia is the most basic form of nitrogenous waste and is formed from the remaining amino acids that occur in the breakdown of proteins

Question 3

NH3

Answer 3

ammonia (NH3),colourless, pungent gas composed of nitrogen and hydrogen.

Question 4

urea

Answer 4

an organic compound with the chemical formula CO (NH2)2. It is produced in the liver and serves as the metabolic by-product of protein and nitrogen metabolism

Question 5

uric acid

Answer 5

a chemical created when the body breaks down substances called purines

Question 6

kidneys

Answer 6

One of a pair of organs in the abdomen. The kidneys remove waste and extra water from the blood (as urine) and help keep chemicals (such as sodium, potassium, and calcium) balanced in the body

Question 7

Osmolarity

Answer 7

the number of dissolved solute particles per liter of solution

Question 8

Excretion

Answer 8

the process of removing wastes and excess water from the body

Question 9

Osmoregulation

Answer 9

maintenance by an organism of an internal balance between water and dissolved materialsregardless of environmental conditions

Question 10

Dehydration

Answer 10

A condition that occurs when the body loses too much water and other fluids that it needs to work normally

Question 11

hypertonic

Answer 11

a solution with a comparatively greater solute concentration than that in another solution

Question 12

Hyperhydration

Answer 12

when the body takes in more water than it loses. Overhydration can occur when people drink much more water than their body needs

Question 13

hypotonic

Answer 13

solutions having a low amount or concentration of the non-penetrating solutes in comparison to the other solution across asemipermeable membrane

Question 14

osmotic potential

Answer 14

The ability of water molecules to migrate over a semipermeable membranefrom a hypotonic solution (more water, fewer solutes) to a hypertonic solution

Question 15

renal vein

Answer 15

The main blood vessel that carries blood from the kidney and ureter to the inferior vena cava

Question 16

renal artery

Answer 16

large blood vessels that carry blood from your heart to your kidneys

Question 17

cortex

Answer 17

The cortex surrounds the inside of the organ, which is called themedulla. The renal cortex itself is covered by the renal capsule, which is a layer of tougher protective tissue. The renal cortex is where the nephrons (blood-filtering units) begin

Question 18

medulla

Answer 18

the inner part of the kidney. The medulla helps regulate the concentration of urine by filtering out water, salts, and acid

Question 19

pelvis

Answer 19

a funnel collecting the urine produced in the kidney, leading to a central “stem,” the ureter

Question 20

ureter

Answer 20

The tube that carries urine from the kidney to the bladder

Question 21

bladder

Answer 21

the organ that stores urine

Question 22

urethra

Answer 22

The tube through which urine leaves the body. It empties urine from the bladder.

Question 23

nephron

Answer 23

the basic structural and functional unit of the kidney. They are the microscopic structure composed of arenal corpuscleand a renal tubule

Question 24

bowman’s capsule

Answer 24

a part of the nephron that forms a cup-like sack surrounding the glomerulus

Question 25

glomerulus

Answer 25

the main filtering unit of the kidney. It is formed by a network of small blood vessels (capillaries) enclosed within a sac called the Bowman's capsule

Question 26

afferent arteriole

Answer 26

a group of blood vessels that supply the nephrons in many excretory systems. They play an important role in the regulation of blood pressure as a part of the tubuloglomerular feedback mechanism

Question 27

efferent arteriole

Answer 27

a blood vessel in the urinary system that brings filtered blood from the glomerulus to the rest of the kidney and back to the general circulation

Question 28

ultrafiltration

Answer 28

a process in the kidney by which urea, salt, water and glucose etc. is extracted from the blood

Question 29

fenestrations

Answer 29

any small opening or pore

Question 30

basement membrane

Answer 30

a ribbon-like extracellular matrix that lies between the endothelium and the podocyte foot processes

Question 31

podocyte

Answer 31

specialized visceral epithelial cells which regulate glomerular filtration

Question 32

filtrate

Answer 32

The liquid that passes through a filter

Question 33

proximal convoluted tubule (PCT)

Answer 33

a segment of the renal tubule responsible for the reabsorption and secretion of various solutes and water. The PCT is located in the renal cortex, the outer part of the kidney, and is the first segment of the renal tubule, where it receives the filtrate from the renal corpuscle

Question 34

Selective reabsorption

Answer 34

the process whereby certain molecules (e.g. ions, glucose and amino acids), after being filtered out of the capillaries along with nitrogenous waste products (i.e. urea) and water in the glomerulus, are reabsorbed from the filtrate as they pass through the nephron

Question 35

microvilli

Answer 35

finger-shaped plasma membrane protrusions that are found at the surface of a large variety of cell types but are most numerous and elaborated on simple epithelial

Question 36

secondary (indirect) active transport

Answer 36

The molecule of interest is then transported down the electrochemical gradient. While this process still consumes ATP to generate that gradient, the energy is not directly used to move the molecule across the membrane, hence it is known as secondary active transport

Question 37

symport

Answer 37

Proteins that move two molecules in the same direction across the membrane

Question 38

osmosis

Answer 38

the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane

Question 39

The loop of henle

Answer 39

long U-shaped portion of the tubule that conducts urine within each nephron of the kidney of reptiles, birds, and mammals

Question 40

descending limb

Answer 40

the portion of the renal tubule constituting the first part of the loop of Henle. Descending limb of loop of Henle. Scheme of renal tubule and its vascular supply

Question 41

ascending limb

Answer 41

a direct continuation from the descending limb of loop of Henle, and one of the structures in the nephron of the kidney. The ascending limb has a thin and a thick segment

Question 42

collecting ducts

Answer 42

The last part of a long, twisting tube that collects urine from the nephrons (cellular structures in the kidney that filter blood and form urine) and moves it into the renal pelvis and ureters

Question 43

antidiuretic hormone (ADH)

Answer 43

A hormone that helps blood vessels constrict and helps the kidneys control the amount of water and salt in the body

Question 44

permeability

Answer 44

the relative ability of solutes to diffuse through the lipid bilayer barrier of membranes.

Question 45

aquaporins

Answer 45

channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells

Question 46

counter-current multiplier

Answer 46

the process in which energy is used to create an osmotic gradient that enables the reabsorption of water from the tubular fluid, so that urine can be concentrated

Question 47

osmoreceptors

Answer 47

a sensory cell located in the hypothalamus that detects changes in osmolality and stimulates the secretion of antidiuretic hormone (AVP) to regulate water balance in the body

Question 48

hypothalamus

Answer 48

The area of the brain that controls body temperature, hunger, and thirst

Question 49

pituitary gland

Answer 49

sometimes called the "master" gland of the endocrine system because it controls the functions of many of the other endocrine glands. The pituitary gland is no larger than a pea, and is located at the base of the brain

Question 50

vasoconstriction

Answer 50

the narrowing (constriction) of blood vessels by small muscles in their walls

Question 51

vasodilation

Answer 51

the widening of blood vessels due to the relaxation of the blood vessel's muscular walls