Sac 2 regulatory

Question 1

Diffusion

Answer 1

A net movement of substances travelling down its concentration gradient
-high concentration to low concentration

Question 2

simple diffusion

Answer 2

When molecules directly go through the cell membrane phospholipid bilayer they are usually small molecules or nonpolar eg carbon dioxide and oxygen passive transport=no energy

Question 3

passive transport

Answer 3

Input energy is not needed (ATP)

Question 4

osmosis

Answer 4

osmosis is the net 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.

Movement of water through a semipermeable membrane(high concentration to low )
Water molecules can travel through cell membrane or through protein channels in larger quantities
Low water= high solute concentration(eg sugar)
-water loves to move towards solute

Question 5

excretory system

Answer 5

In mammals, the excretory system is responsible for removing metabolic and other wastes (excess, unnecessary or dangerous materials)from the blood and plays a role in water balance.maintaining homeostasis or internal environmental balance

The Excretory system in consists of organs (skin, the liver, the lungs and the kidney) which are responsible for the elimination of metabolic wastes

Question 6

what are the Harmful wastes, Nitrogenous wastes such as(n-waste)

Answer 6

ammonia and urea from the metabolism of protein
creatine and creatinine from the metabolic activities of skeletal muscle.

Question 7

Nephrons purpose

Answer 7

Goal is to process waste products from the blood to create urine (functional unit of a kidney)

Question 8

Glomerular filtration includes

Answer 8

Glomerular filtration:
Blood pressure forces fluid from the blood in the glomerulus into the bowman’s capsule
The filtrate contains a mixture of glucose, salts, vitamins, nitrogenous wastes and other small molecules

Question 9

Tubular reabsorption includes

Answer 9

Reabsorption is the process by which water and useful solutes are removed from the filtrate and returned to the blood. The major site of reabsorption is the proximal tubule

When the filtrate exits the glomerulus, it flows into a duct in the nephron called the renal tubule. As it moves, the needed substances and some water are reabsorbed through the tube wall into adjacent capillaries.

move by simple diffusion, facilitated diffusion or active transport(require atp) from the tubule into the surrounding capillaries.

All nutrients, such as glucose and amino acids, and most of the water and inorganic ions, such as sodium, potassium, phosphate and calcium are reabsorbed across the wall of the proximal tubule and enter the peritubular capillaries of the blood stream

Question 10

Tubular secretion:

Answer 10

Tubular secretion:
Secretion is the process of transporting specific compounds, typically waste products, out of the blood of the peritubular capillaries into the tubular filtrate that will eventually become urine. Secretion occurs mainly in the proximal tubule, but some also occurs in other regions of the tubules

Secretion occurs mainly by active transport, but some also occurs by passive diffusion

Question 11

substances that are Excreted:

Answer 11

Excess water and solutes such as urea, uric acid ammonia creatinine as well as ions such as sodium and chloride are eliminated in the form of urine.
Urine is transferred out of the kidneys via collecting ducts in the ureters

Question 12

glomerulus

Answer 12

filters small solutes from the blood

Question 13

proximal convoluted tubule

Answer 13

reabsorbs ions, water and nutrient removes toxins and adjusts filtrate pH

Question 14

distal tubule

Answer 14

selectively secretes and absorbs different ions to maintain blood PH balance

Question 15

collecting duct

Answer 15

reabsorbs solutes and water from the filtrate

Question 16

loop of henle

Answer 16

Its main function is to reabsorb water and sodium chloride from the filtrate. This conserves water for the organism, producing highly concentrated urine.

Question 17

Negative Feedback:

Answer 17

Negative Feedback:
A negative feedback loop is a process in which the body senses a change in a variable and activates mechanisms to reverse the change. Negative feedback is a key component of homeostatic control loops that regulate many body variables and maintain the body’s internal conditions within narrow limits.
a stimulus response mechanism where a change in a variable is detected (the stimulus) and a response occurs which reverses the direction of change, bringing the variable back within normal range.

Question 18

stimulus–response

Answer 18

stimulus–response model a representation of an action that starts with a stimulus and ends with the response to that stimulus

Question 19

major source of n-waste

Answer 19

urea and ammonium

Question 20

describe the composition of the filtrate in the bowmans capsule, how is it different to blood plasma

Answer 20

the filtrate leaving the Bowman’s capsule is very similar to blood plasma (filtrate or glomerular filtrate is composed of blood plasma minus plasma protein i.e. it contains all the components of blood plasma except the proteins)

Question 21

specific substances that are typically reabsorbed by the kidneys

Answer 21

Most of the reabsorption of solutes necessary for normal body function, such as amino acids, glucose, and salts, takes place in the proximal part of the tubule. This reabsorption may be active, as in the case of glucose, amino acids, and peptides, whereas water, chloride, and other ions are passively reabsorbed.

Question 22

substances being secreted

Answer 22

hydrogen, creatinine, ions, and other types of waste products, such as drugs.

Question 23

osmoregulation

Answer 23

The process by which an organism regulates the water balance in its body and maintains the homeostasis of the body is called osmoregulation. Osmoregulation is the maintenance of a constant osmotic pressure of the body fluids within a normal range

Controlling water balance is important to ensure the cells of the body are in equilibrium

Too much water outside cells and the cells will absorb it, possibly lysing(the breakdown of a cell caused by damage to its plasma (outer) membrane.)

Too little water inside cells and the cells will release water, possibly collapsing

Question 24

What is the renal artery afferent and efferent arteriole?

Answer 24

Afferent arterioles deliver blood to the glomerulus, and efferent arterioles carry blood away from the glomerulus.

Afferent: approaching nephron=high oxygen, lower carbon dioxide, high urea, unbalanced ions and water

Efferent: leaving nephron=lower oxygen, higher carbon dioxide, lower urea, balanced ions and water.

Question 25

Peritubular capillaries

Answer 25

Peritubular capillaries are tiny blood vessels in your kidneys. They filter waste from your blood so the waste can leave your body through urine (pee)

Question 26

renal artery and vein

Answer 26

Renal Veins carry filtered blood from the kidneys to the posterior vena cava. Renal Arteries carry unfiltered blood from the aorta to the kidneys.

Question 27

3 major n-waste excreted, Advantage and
Disadvantage

Answer 27

N waste
Advantage
Disadvantage

Ammonia

Less energy to produce
Highly toxic requires a lot of water

Urea

Moderate energy required to produce
Still requires water for excretion, so water loss still an issue

Uric acid

Very little water required, low toxicity
High energy cost for production

Question 28

how does the structure of a proximal tube aid its function

Answer 28

Reabsorption from the proximal tubule to the blood is enhanced by the presence of microvilli on the epithelium
that greatly increase the surface area available for reabsorption

Flattened, thin shape. Flattened thin shape and microvilli/folding of membrane exposed to lumen increases the surface area over which reabsorption can take place, thus allowing more particles to be reabsorbed at the same time and therefore increasing the efficiency of reabsorption.

Abundant mitochondria: provide the ATP required for the active transport of amino acids/glucose. To move materials against their concentration gradient requires the expenditure of energy. This energy is provided by ATP, which is produced for the cells use by the mitochondria. Without these not all of the glucose and amino acids would be reabsorbed.

Question 29

How Feature assists osmoregulation:
Long and short proximal convoluted tubule

Answer 29

Long proximal convoluted tubule: increases water reabsorption
Found in marine fish
Greater surface area for reabsorption to occur
Short proximal convoluted tubule: decreases water reabsorption
Found in freshwater fish
Less surface area for reabsorption to occur

Question 30

How Feature assists osmoregulation:
Small or large glomeruli & bowman’s capsule

Answer 30

Small glomeruli & bowman’s capsule: reduces filtration rate
Found in saltwater fish
Less volume of filtrate
Saltwater fish lose toxic ammonia over gills, the kidney is not required to filter N-waste form blood
Minimise water loss in urine
Large glomeruli & Bowman’s capsule increase filtration rate: maximise filtration rate
Greater volume of filtrate, increase water loss in urine

Question 31

How Feature assists osmoregulation:
Large or small loop of Henle

Answer 31

Large loop of Henle: increases water & ion reabsorption
Found in terrestrial organisms that live in dry environments and need to conserve water
Increases water reabsorption
Minimise water loss in urine
Excrete highly concentrated urine

Small loop of Henle: reduces water & ion reabsorption.
Found in organisms that live in moist environments
Less water reabsorption
less concentrated urine excreted

Question 32

How Feature assists osmoregulation:
degree of Vascularization(the number of blood vessels in a tissue)

Answer 32

Heavy vascularisation = large surface area for rapid reabsorption of water and solutes back into the bloodstream
= more reabsorption

Light vascularisation = small surface area, decrease reabsorption of water back into the bloodstream

Question 33

what is the urinary system

Answer 33

The urinary system’s function is to filter blood and create urine as a waste by-product. The organs of the urinary system include the kidneys, renal pelvis, ureters, bladder and urethra. The body takes nutrients from food and converts them to energy