Ocr Biology F214 Hormones And Excretion

Front 1

What are Hormones?

Back 1

Molecules released by endocrine glands which act as messengers and are secreted directly into the blood.

Front 2

What is an Endocrine Gland?

Back 2

A gland which secretes hormones directly into the blood. They have no ducts.

Front 3

What is an Exocrine Gland?

Back 3

A Gland which secretes molecules into a duct which carries molecules to where they are used.

Front 4

Describe the features of Peptide hormones.

Back 4

Water soluble, transported in blood plasma, binding releases adenylate cyclase which converts ATP to cAMP acting as a second messenger triggering a cascade effect on cytoplasmic enzymes.

Front 5

Describe features of steroid hormones.

Back 5

Insoluble, Transported in a carrier through blood plasma, diffuses through membrane and binds to an intracellular receptor to be transported to the nucleus to increase transcription and translation.

Front 6

What effects does the Adrenal Medulla have?

Back 6

Relaxes smooth muscle in bronchioles, increase heart rate, cause vasoconstriction to increase blood pressure, stimulate conversion of glycogen to glucose, dilate pupils, increase awareness.

Front 7

What effects does the Adrenal Cortex have?

Back 7

Mineralocorticoids help to control Na and K concentrations in the blood. Glucocorticoids help to control metabolism of carbohydrates and proteins in the liver.

Front 8

What is the Exocrine function of the Pancreas?

Back 8

Acinar cells secrete digestive enyzymes which digest food into the pancreatic duct. They are found in clusters around the duct.

Front 9

What is the Endocrine function of the Pancreas?

Back 9

Islets of Langarhans are made up of alpha cells which secrete glucagon and Beta cells which secrete insulin. They are secreted into the bold.

Front 10

What are the effects of insulin?

Back 10

More glucose channels place onto membrane so more glucose enters cell. Glucose is converted into glycogen and fats, and more is used in respiration.

Front 11

What are the effects of glucagon?

Back 11

conversion of glycogen to glucose, use of more fatty acids in respiration. Glucose id produced from amino acids and fats.

Front 12

What is Glycogenesis?

Back 12

Conversion of Glucose to Glycogen.

Front 13

What is Glycogenolysis?

Back 13

Conversion of glycogen to glucose.

Front 14

What is Gluconeogenesis?

Back 14

The production of glucose by conversion from amino acids and fats.

Front 15

How is insulin secretion controlled?

Back 15

When glucose concentrations are high, glucose enters the cell and is metabolised producing ATP. The extra ATP cause K ion channels to close which makes the cell less negative causing Ca channels to open and insulin to be secreted as insulin vesicles fuse with the membrane and release insulin.

Front 16

What is Diabetes Mellitus?

Back 16

A disease in which glucose concentrations cannot be controlled effectively.

Front 17

What is Type 1 Diabetes?

Back 17

Also Known as Insulin Dependent/Juvenile onset. The result of an autoimmune response so the body is no longer able to manufacture insulin and cannot store excess glucose. Treatment involves monitoring and insulin injections.

Front 18

What is Type 2 Diabetes?

Back 18

Non-insulin dependent. Insulin is still produced but responsiveness declined due to decline of receptors on liver and muscle cells. Treatment involves controlling diet and injections.

Front 19

What are the risk factors of Type 2 diabetes?

Back 19

Obesity, High sugar diet, Asian/Afro-Caribbean origin and family history.

Front 20

How does the nervous system control heart rate?

Back 20

The Sino-Atrial node generates electrical impulses. The rate of impulses is controlled by the medulla oblongata. Stimuli are recepted by Baroreceptors in the aorta and vena cava and Chemoreceptors in the aorta, carotid artery and medulla.

Front 21

How does the Hormonal system control heart rate?

Back 21

Adrenal glands secrete adrenaline which binds to specific receptors in the heart causing cardiac muscle to contract more frequently and with more force.

Front 22

What is excretion?

Back 22

The removal of metabolic waste from the body.

Front 23

Why does Carbon Dioxide need to be excreted?

Back 23

Too many Hydrogen ions present will reduce oxygen transport. It might also make the blood too acidic leading to Respiratory Acidosis which causes breathing difficulties, drowsiness, and confusion.

Front 24

Why do nitrogenous compounds need to be removed?

Back 24

Ammonia is highly toxic.

Front 25

Describe the Gross structure of the liver.

Back 25

Blood travels from the aorta supplying oxygen for aerobic respiration. Deoxygenated blood enters via the hepatic portal vein rich in the products of digestion. The bile duct carries bile from the liver to the gall bladder for storage.

Front 26

Describe the histology of the liver.

Back 26

Lobules are made up of hepatocytes, they have a central vein. The hepatic artery and vein are connected by sinusoids. Blood runs through the Sinusoids, past the hepatocytes which remomve harmful substances. Kupfer cells remove bacteria and break down old red blood cells. The bile duct connect to the CV by canaliculi.

Front 27

How is Urea Formed.

Back 27

1. Deamination- Amino acid + Oxygen= Keto acid (to respiration) and Ammonia.

2. The Ornithine Cycle- ammonia +carob dioxide= Urea and water

Front 28

How is Alcohol detoxified?

Back 28

Ethanol is oxidised to Ethanal (using NAD) and this is oxidised to ehtanoic acid which is oxidised to acetyl Coenzyme A

Front 29

Describe the process of Ultrafiltration.

Back 29

The efferent arteriole is smaller in diameter than the afferent arteriole, sothere is a high hysrostatic pressure in the glomerulous. This forces liquid and small molecules into the renal capsule, the liquid passes through three layers (Basment, epithelium, and capillary wall) so larger molecules cannot fit through/

Front 30

Describe the process of Selective re-absorption.

Back 30

The epithelium of the PCT wall has microvilli to provide a large surface area. Useul solutes are reabsorbed by active transport and facilitated diffusion. Some urea is reabsorbed. Water enters the blood by osmosis from the loop of Henlé and the DCT.

Front 31

What does Urine usually contain and what does is not usually contain?

Back 31

Usually contains: Water, dissolved salts, urea, hormones and excess vitamins.

Doesn't usually contain: Proteins, blood cells, glucose, amino acids, vitamins.

Front 32

Describe the process of Osmoregulation.

Back 32

At the top of the AL, sodium and chloride ions are actively pumped into the medulla. Water stays inside as the AL is impermeable to water creating a low WP. Water moves out of the DL making the filtrate more concentrated. Na and Cl diffuse into the medulla at the bottom of the AL lowering WP and increasing ion conc so water moves out of the collecting duct.

Front 33

What is the significance of the length of the loop of Henlé?

Back 33

The longer the loop, the more water can be reabsorbed. More ions can be actively pumped out creating a lower WP so more water moves out of the nephron.

Front 34

Describe hormonal control of water reabsorption.

Back 34

Osmoreceptors in the hypothalamus detect change in water potential which stimulates the posterior pituitary gland to release more or less ADH which alters the permeability of the collection duct.

Front 35

What are the causes of Kidney failure?

Back 35

Infection can cause inflammation and damage which interferes with filtering and reabsorption. High blood pressure can damage glomeruli so larger molecules can be filtered out.

Front 36

What are the problems associated with Kidney failure?

Back 36

Build up of waste products, accumulation of fluid in tissues, unbalanced ion concentration and anemia.

Front 37

What are the advantages and disadvantages of Renal Dialysis?

Back 37

ADVANTAGES- Less risky and no problem with rejection.

DISADVANTAGES- Time constraint, costly, inconvenient and the patient can feel unwell.

Front 38

What are the advantages and disadvantages of Kidney transplants?

Back 38

ADVANTAGES- Cheaper, more convenient, patients don't feel unwell.

DISADVANTAGES- operation is risky, risk of rejection and use of immunosupressant drugs.

Front 39

Describe the process of testing for pregnancy.

Back 39

The stick contains immobilised antibodies for hCG bound to a coloured bead. When urine is applied hCG will bind to the antibody. If hCG is present the test strip turns blue because the antibody binds to the blue beads.

Front 40

Describe the process of testing for Steroids.

Back 40

Gas Chromatography- the sample is vaporised and passed through a column containing a liquid. The time taken for the sample to pass through is recorded and compared to known times for steroids.