Excretion

What is produced during metabolic reactions?

Waste products.

What are waste products in plants?

• Oxygen.

• Carbon dioxide.

• Water vapour.

• Unwanted chemical substances.

What occurs during the day in plants?

• During the day there is sufficient amount of light.

• Photosynthesis will occur.

• More oxygen is releases, less carbon dioxide is released.

• Oxygen is in excess and becomes a waste product.

What occurs during the night in plants?

• The is insufficient amounts of light.

• Respiration will occur.

• More carbon dioxide will be release, less oxygen will be released.

• Carbon dioxide will be in excess and become a waste product.

How do gases (waste products) leave the plant?

• Whichever is in excess leaves through the stomata via diffusion.

How is water lost?

Transpiration.

How are chemical substances removed?

Plant cells break down unwanted molecules into chemical waste, which is stored in dying tissues; when these tissues fall off, the waste is removed from the plant.

What is excretion?

Its the removal of harmful metabolic waste.

What are the waste products in humans?

• Carbon dioxide

• Urea

• Other substances in excess

Why should waste materials be removed efficiently?

• High concentrations are toxic to the human body.

• High carbon dioxide levels reduce enzyme activity as it lower the pH of the cells.

What is the definition of the osmotic effect?

• Body fluids have a higher concentration of waste products.

• Causes water to move out of cell that’s changes their water potential and ability to carry out chemical reactions.

What are the excretory organs?

1. Kidneys → urine (gets rid or urea)

2. Lungs → exhalation (gets rid of co2)

3. Skin → sweating (water and mineral ions)

What is the role of the kidneys?

1. Regulate water content in the body → blood pressure + osmoregulation.

2. Excrete toxic waste products of metabolism → urea and salts.

What is osmoregulation?

The process of maintain the bodies water and salt concentration across body membranes (osmotic balance).

Importance of osmoregulation

Cell cytoplasm + blood plasma are mainly water:

• Too much water causes the swelling of cells.

• Too little water dehydrated cells and could cause cell death.

How is water lost in the body?

• Lungs during exhalation.

• Sweat.

What are the sources of water in the body?

• Aerobic respiration.

• Diet.

What are the functions the urinary system?

1. Filter waste products from the blood and eel them.

2. To control the water levels in the body.

What does the urinary system consists of?

1. Two kidneys.

2. Bladder.

3. Ureters

4. Urethra.

5. Renal artery.

6. Renal vein.

What do the kidneys do?

They filter the blood.

What is the role of the ureter?

Connects the kidney to the bladder, moves filtered substances to be stored in bladder.

Role of the bladder?

Stores urine (excess water, salts and urea) as it is produced by the kidneys.

What is the role of the urethra?

Tune that connects the bladder to the exterior where the urine is released.

What are the three regions of the kidney?

1. Cortex → outermost region

2. Medulla → inner section

3. Renal pelvis → tube linking kidney to ureter

What are the sections of the nephron?

• Bowmans capsule surrounded by the glomerulus (network of capillaries)

• Proximal convoluted tubule

• Loop of Henlé

• Distal convoluted tubule

• Collecting duct

What are the Proseccos in the kidney in order?

1. Ultrafiltration

2. Selective reabsorption of glucose

3. Selective reabsorption of water and salts

What is the prosaic of ultrafiltration?

1. Arterioles branch of the renal artery, into the nephron and forma bundle of capillaries called the glomerulus inside of the Bowmans capsule.

2. The capillaries are narrow and increase the pressure of blood flow.

3. Large molecules such as proteins can’t pass through the gaps.

4. Smaller molecules forced out and become a part of the glomerular filtrate.

5. Sometime get reabsorbed.

What substances are filtered out of the blood during ultrafiltration?

1. Glucose

2. Water

3. Urea

4. Salts

What substances are too large to be filtered?

1. Proteins

2. Red blood cells

What is the presence of blood or proteins in the urine a sign of?

High blood pressure.

Where is glucose reabsorbed?

Proximal convoluted tubule

How is glucose reabsorbed?

• Active transport (tubule has a lot of mitochondria)

• Can only occur at the proximal convoluted tubule as its the only one that facilitates active transport

Hoe can you tell a person had diabetes?

Glucose will be present in their urine.

• High glucose levels

• Not all can be reabsorbed back into the blood

Where are salts reabsorbed?

Loop of Henle’

• Both diffusion and active transport

Where is water reabsorbed?

Collecting duct via osmosis

What is water important for?

Osmoregulation

What is negative feedback?

When corrective measure is turned of to return the levels to the original state.

What controls water reabsorption?

ADH hormone

What causes the actions of ADH?

The hypothalamus detects change, sends signals to the pituartm gland to release or stop the release of ADH.

What happens when the water content in the body is too high?

• The hypothalamus detects this change.

• Sends signals to the pituitary gland to stop releasing ADH.

• Collecting duct becomes less permeable to water.

• Less water is reabsorbed into the blood.

• More dilute urine.

What happens when the water content in the body is too low?

• Hypothalamus detects this change.

• Send signals to pituitary gland to release ADH.

• Collecting duct becomes more permeable to water.

• More water is reabsorbed into the blood.

• Less dark urine.

What other factors affect urine condition?

Higher temp more water loss, smaller amount of dark, highly concentrated urine.