Gossip-blood groups

What is the “Do Now” task about?

Label the parts of the digestive system.

Why do all cells require nutrients?

All cells require nutrients to provide energy for the cell’s activities and materials for cell growth, production, secretion, and other metabolic processes.

What is the main function of the digestive system?

The digestive system extracts nutrients from food and absorbs them into the body for use by the cells.

What are the six basic functions of the digestive system?

1. Ingestion of food and water 2. Mechanical digestion 3. Chemical digestion 4. Movement of food along the alimentary canal 5. Absorption of digested food and water 6. Elimination of unabsorbed material.

What is digestion?

Digestion is the process of breaking down food into particles small enough to be absorbed into the bloodstream.

What are the two types of digestion?

Mechanical digestion and chemical digestion.

What is mechanical digestion?

Mechanical digestion is the physical breakdown of food particles.

Where does mechanical digestion occur and how?

In the mouth (chewing), stomach (churning), and small intestine (bile emulsifying fat).

Why is breaking food into smaller pieces important?

It increases surface area for more effective chemical digestion.

What is chemical digestion?

Chemical digestion uses enzymes to break down large, complex molecules into smaller, simpler molecules.

What is the alimentary canal?

The continuous tube that runs from the mouth to the anus through which food passes.

What are accessory organs, and which organs are included?

Accessory organs are part of the digestive system but not part of the alimentary canal, including the liver, pancreas, gall bladder, and salivary glands.

What mechanical digestion happens in the mouth?

Chewing and swallowing; teeth break food down to increase surface area.

What prevents food from entering the wrong places when swallowing?

The epiglottis prevents the bolus from entering the trachea, and the uvula prevents it from entering the nasal cavity.

What chemical digestion occurs in the mouth?

Salivary amylase digests polysaccharides (starch) into disaccharides (maltose).

What are incisors like and what is their function?

Shape: Chisel-shaped; Function: Cutting.

What are canines like and what is their function?

Shape: Pointed and sharp; Function: Tearing and ripping.

What are premolars and molars like and what is their function?

Shape: Broad and flat; Function: Crushing and grinding.

How many of each type of tooth are there?

Incisors: 4, Canines: 2, Premolars: 4, Molars: 6.

What is the oesophagus?

A long tube connecting the pharynx to the stomach.

What type of muscles does the oesophagus contain, and what do they do?

It contains a double layer of muscle that constricts and pushes the bolus into the stomach.

What is the wave-like motion in the oesophagus called?

Peristalsis.

What are the mechanical processes of the stomach?

Churning mixes food with gastric juice; the extra oblique muscle layer allows for mixing.

What are the chemical processes of the stomach?

Hydrochloric acid activates pepsinogen to form pepsin, which digests proteins into shorter polypeptides.

What controls the movement of chyme from the stomach to the small intestine?

The pyloric sphincter.

What does the lining of the stomach secrete?

Gastric juice from the gastric glands in gastric pits.

What does gastric juice contain?

Hydrochloric acid, mucus, and digestive enzymes.

How long is the small intestine and what are its three parts?

Roughly 7 meters long; Parts: Duodenum, Jejunum, Ileum.

What mechanical digestion occurs in the small intestine?

Segmentation narrows the intestine, mixing bolus with juices and bile.

What chemical digestion occurs in the small intestine?

Pancreatic juice contains many enzymes; intestinal juice also contains enzymes.

Where is bile produced, stored, and secreted?

Produced in the liver, stored in the gall bladder, secreted into the duodenum.

What is the function of bile?

Emulsifies fat, breaking it into smaller droplets for chemical digestion by lipases.

What type of digestion is emulsification?

Mechanical digestion.

Where is pancreatic juice secreted and what does it do?

Secreted from the pancreas into the duodenum; helps neutralise stomach acid.

What are the enzymes in pancreatic juice and their functions?

Pancreatic protease (digests polypeptides), amylase (digests starch), lipase (digests fats), nucleases (digest RNA and DNA).

Where is intestinal juice secreted and what does it contain?

It is secreted in the small intestine and contains enzymes like maltase, sucrase, lactase, intestinal lipase, and peptidase.Maltase – Breaks down maltose into two glucose molecules.

• Sucrase – Breaks down sucrose into glucose and fructose.

• Lactase – Breaks down lactose into glucose and galactose.

• Intestinal lipase – Breaks down fats into glycerol and fatty acids.

• Peptidase – Breaks down small peptides into amino acids

The enzyme pepsin is secreted by which organ and what does it digest?

Stomach; digests proteins.

Digestive enzymes and hydrochloric acid do not digest the stomach wall because:

The mucus lining protects the stomach wall cells from enzyme activity.

People who develop gallstones sometimes have their gall bladder removed. What type of nutrient do they need to avoid?

Fats/lipids; Examples include butter, cheese, oils.

What role do enzymes play in digestion of macromolecules?

Enzymes break down macromolecules into smaller units for absorption.

Which organs are involved in the digestion of proteins and lipids, and how?

Stomach (pepsin), pancreas (produces proteases and lipases), small intestine (produces peptidase and lipase for final breakdown).

What is the role of external organs that produce secretions aiding digestion?

Liver (produces bile), pancreas (produces pancreatic enzymes), salivary glands (produce saliva with amylase).

What is the description of bile?

Bile emulsifies fat.

What is the description of pepsin?

Pepsin is the activated form of pepsinogen.

What is the description of amylase?

Amylase digests starch into maltose.

What is the description of hydrochloric acid?

Hydrochloric acid activates pepsinogen.

What is the description of trypsin?

Trypsin digests polypeptides into peptides.

What is the description of peptidase?

Peptidase breaks down peptides into amino acids.

What happens to the products of digestion in the small intestine?

They are absorbed into the blood.

Why does the small intestine need a large internal surface area?

To increase absorption of nutrients into the bloodstream.

How is a large surface area achieved in the small intestine?

Length (6–7m), mucosal folds, villi, each villus having microvilli.

What is the structure of a villus ideally suited for?

Its structure suits its function of nutrient absorption.

How long is each villus?

Approximately 1 mm long.

What type of cell layer does each villus have?

A single layer of cells.

What does each villus contain internally?

A lacteal (lymph capillary) surrounded by blood capillaries.

On what does the method of absorption depend?

It depends on the type of molecule being absorbed.

What are the two main transport routes for absorbed nutrients in the villi?

Blood capillaries and lacteals.

What substances are absorbed into blood capillaries from the villi?

Simple sugars, amino acids, water, and water-soluble vitamins.

After absorption into blood capillaries, where are these substances transported?

They are carried via blood to other cells or processed in the liver.

What substances are absorbed into lacteals?

Fatty acids and glycerol.

What happens to fatty acids and glycerol in the cells of the villi?

They recombine to form fats with fat-soluble vitamins.

How are these fats transported after recombining?

They are transported by the lymphatic system.

How does the large intestine compare in size to the small intestine?

It is shorter but has a larger diameter.

What are the four parts of the large intestine?

Caecum, colon, rectum, and anus.

What is the caecum and what is attached to it?

The caecum is where the small intestine joins the large intestine, the appendix is attached to it.

What is the colon?

The U-shaped part of the large intestine.

What is the rectum?

The last part of the large intestine.

What is the anus?

The external opening at the end of the rectum.

How long does material typically move through the large intestine?

Approximately 18–24 hours.

What are the two main functions of the large intestine?

Absorption of water and further processing of organic compounds by bacteria.

What do bacteria in the large intestine release during the breakdown of compounds?

Vitamins and minerals.

What remains after absorption in the large intestine?

Faeces.

What are the components of faeces?

Water, undigested food, bacteria, bile pigments, remains of cells from the alimentary canal.

Why is “defecation” better referred to as “elimination”?

Excretion refers to metabolic wastes; elimination is removal of undigested waste.

What is the nature of the material left in the colon after water absorption?

Semi-solid material.

How does the semi-solid material move into the rectum?

It is pushed by peristalsis.

What triggers the process of defecation?

The stretching of rectum walls as they fill with faeces.

How is faeces expelled from the body?

The anal sphincter relaxes, allowing faeces to pass out.

What is the “Do Now” task for this lesson?

Read Procedure for Act 5.6 – Blood Grouping Practical, and copy the table into your books.

What are antigens?

Sugar/protein markers that label red blood cells as a particular type.

What type of blood does a person have if their RBCs contain only the A antigen?

Type A blood.

What type of blood does a person have if their RBCs contain only the B antigen?

Type B blood.

What type of blood does a person have if their RBCs contain both A and B antigens?

Type AB blood.

What type of blood does a person have if their RBCs contain neither A nor B antigens?

Type O blood.

What are antibodies?

Substances produced that attack and destroy foreign cells by recognizing antigens.

Which antibody is produced by a person with Type A blood?

Antibody B.

Which antibody is produced by a person with Type B blood?

Antibody A.

Which antibodies are produced by a person with Type AB blood?

No antibodies produced.

Which antibodies are produced by a person with Type O blood?

Both Antibody A and B.

How are the antibodies a person produces related to their blood type?

The antibodies produced are opposite to their blood type.

What is the Rh blood group related to?

The D antigen and the antibody present in blood.

What is the antigen/antibody status of a person with Rh-negative blood?

No antigen present, but D antibodies are produced.

What is the antigen/antibody status of a person with Rh-positive blood?

D antigen present, no antibodies produced.

What two factors must be considered when determining blood compatibility?

Antibodies in the recipient's plasma and antigens on the donor's RBCs.

Why can a person with Type A blood not donate to a person with Type B blood?

The recipient has A antibodies, which would attack A antigens on the donor's RBCs.

What are the three steps of the Blood Group Practical?

Collect Materials, Collect Data, Discuss Results.

What blood type is considered a universal donor and why?

Type O; Has no antigens on RBC.

If all donors’ blood bags are unlabelled, who could the blood be given to and why?

Recipient: Blood Type AB+; has no antibodies in plasma.

A patient with A- blood needs a transfusion. Which blood types can they receive?

They can receive Blood Type A or O.

What are the main chambers of the heart and their functions?

Atria receive blood; ventricles pump it.