Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

EXCRETION

KEY CONCEPTS
● Definition: The removal of metabolic waste from the body
...

● Major excretory organs;
○ Lungs
...

○ Bladder
...

● The need for excretion → if excretion didn’t occur then there would be a build

up of toxic/ harmful products which can then harm our body cells
...


● Respiratory acidosis;
○ Excess CO₂
○ CO₂ H₂ → H₂ ₃
+
O
CO
○ H₂ ₃ HCO₃ + H
CO →
⁻
○ An increase in the H decreases the blood’s pH, this is detected by the

respiratory system in the medulla oblongata
...

○ In red blood cells the enzyme ​
carbonic anhydrase​
breaks down the

carbonic acid​ ₂ ₃
(H CO )
...


1
...

● Amino acid + oxygen → keto acid + ammonia

● Amino acids contain a lot of energy so are used in respiration
...


2
...

● This all occurs in the liver
...


1

ROLES
● Processes and stores nutrients from the small intestine e
...
glucose
...

● Detoxification of alcohol/ drugs
...

● Produces bile
...

● Conversion of glucose to fatty acids
...

● Transamination
...

● Lots of mitochondria, smooth/rough ER and microvilli etc
...

● Bile Canaliculus - the hepatocytes secrete bile into the narrow tubes

(canaliculus) which permeate the live
...

● Macrophages are found in the blood, they locate and engulf microscopic foreign

bodies
...

● Alcohol is detoxified in the hepatocytes (liver cells) in the liver
...


1
...


2
...


3

● NAD is used to break down the fatty acids for use in respiration
...
This is all because reduced NAD cannot be
used in respiration
...

● Renal Capsule;
○ Tough, fibrous layer
...

○ Offers protection
...

○ Where ultrafiltration takes place
...

● Renal Pelvis;
○ Where collection of urine occurs before feeding into the ureter
...

○ They are the functional unit of the kidney
...

○ Each kidney has around 1
...

○ Bowman's capsule → Proximal convoluted tubule → Loop of Henle →

Distal convoluted tubule → Collecting duct
...


● The blood flow; Afferent arteriole → Glomerulus → Efferent arteriole
...


○ The afferent and efferent arterioles have different diameters
...

● There are 3 layers between the glomerulus and the Bowman’s capsule;

1
...

● Narrow gaps between cells that make up the walls of capillaries
...


2
...

● Mesh of collagen fibres and glycoproteins
...
Epithelial cells of the Bowman’s capsule
...


5

● The gaps allow fluid pushed out of the glomerulus to enter the Bowman’s

capsule
...

● The ​
filtration pressure​
determines the rate of filtration
...


○ Water potential = solute potential + hydrostatic pressure

Blood of Glomerulus
● Blood cells;
○ Red Blood
Cells
...

○ Platelets
...

● Water
...

● Amino Acids
...

● Inorganic ions/
salts
...


Things left in the
Glomerulus

Filtrate of the Bowman’s
Capsule
...

○ White Blood
Cells
...

● Plasma proteins
...

Glucose
...

Urea
...

● Vitamins/ drugs
...
C
...

● All glucose, amino acids and some water and ions are reabsorbed
...
C
...

○ Microvilli ■ Increase the surface area for reabsorption
...
c
...

■ Facilitated diffusion
...

○ The cells of the p
...
t
...


1
...
c
...
Via ​
active transport​

...

6

2
...

3
...

● Via facilitated diffusion - down the concentration gradient and is a

passive process
...

4
...

5
...


6
...


LOOP OF HENLE
● The role of the loop of Henle is to create a very negative ​ater potential​ the
w
in

tissues of the medulla
...

1
...

2
...

3
...

4
...

in
5
...

6
...

7
...


7

8
...

9
...

in
● Countercurrent multiplication

DISTAL CONVOLUTED TUBULE
● At the top of the loop of the Henle, the filtrate is dilute
...
c
...

● As a result, the fluid arriving at the collecting duct has a very high water

potential
...


This area also contains the axon terminals of the neurons whose cell bodies lie
8

in the hypothalamus
...
- monitor the amount of water in the

blood
...

○ If the water content of the blood is low then water is lost from the

osmoreceptors by osmosis
...

○ This action potential cause ADH to be released from the end of the

neurone into the blood capillaries of the posterior pituitary gland
...

● ADH acts on the plasma membrane of cells that make up the wall of the

collecting duct
...

1
...

2
...

3
...

4
...

● When the body is overhydrated ADH is inhibited
...

● Causes;
○ Diabetes Mellitus (type 1 or 2)
...

○ Infection
...
g
...

■ Rapidly lead to death
...

○ Removes wastes, excess fluids and salts by passing the blood over a

dialysis membrane
...
Dialysis fluid is a complex solution that matched the
composition of body fluids
...

○ Any substances that are too low in concentration diffuse into the blood

from the dialysis fluid
...

● Haemodialysis;
○ Blood from a vein is passed into a machine that contains an artificial

membrane
...

○ This must happen 3 times a week, hours each session
...

○ Disadvantages;
■ 3 times a week
...

● Peritoneal dialysis;
○ The filter is the body's own abdominal membrane
...

○ Dialysis fluid is pushed through; this fills the space between the organs

and the abdominal wall
...

○ Advantages;
■ Performed at home
...

● Kidney Transplant;
○ Old kidneys are left in place; unless infectious or cancerous
...

○ Patient under anaesthesia
...

○ The body will recognise the foreign object so immunosuppressant drugs

will be required
...

■ Diet is less limited
...


10

■ No longer seeing oneself as chronically ill
...

■ Major surgery under a general anaesthetic
...

● Bleeding
...

■ Frequent checks for sign of organ rejection
...

● High blood pressure
...


Pregnancy Testing;
● Human chorionic gonadotrophin (hCG) is a relatively small glycoprotein and a

pregnancy hormone that embryos start secreting
...

● If a mobile, monoclonal antibody detects hCG in the urine it will bind to it and

the complex will move up the strip with the urine
...
This causes the antibodies containing a blue bead to be held in one
place forming a blue line
...
It is a control as it

shows that the antibodies are mobile and can move to the end of the strip
...


● They can give advantages in competitive sports and have dangerous side effects
...

● Relatively small molecules and can enter the nephron easily
...

gas
or

11

● The sample is vaporised and passed down a long tube lined by an absorption

agent
...

● The substance then comes out of the gas and is absorbed onto a lining
...

● Drugs can be identified and quantified in the chromatograms

---