Explanation

The correct order of the alimentary canal, also known as the gastrointestinal (GI) tract:

• Mouth: Food enters the mouth, where it's chewed and mixed with saliva.
• Oesophagus: Food passes through the oesophagus, a muscular tube that transports it to the stomach.
• Stomach: The stomach secretes gastric juices to digest proteins and fats.
• Small Intestine: Nutrient absorption occurs in the small intestine, where specialized structures like villi and microvilli increase the surface area.

Last verified on 15-03-2026

Explanation

• Humans have 20 primary teeth (also known as deciduous or baby teeth).
• 32 permanent teeth (also known as adult teeth).

Explanation

• Respiration (breathing) is mainly controlled automatically by the brain’s respiratory center in the medulla oblongata.
• Normally, breathing occurs without conscious control, so it is an involuntary process.
• When a person cannot control breathing voluntarily (e.g., during sleep or unconsciousness), the body automatically continues respiration.

Last verified on 13-03-2026

Explanation

• Enamel is the hard, mineralized outer layer of teeth.
• It protects the inner parts of the tooth from damage and decay.
• Enamel is the hardest substance in the human body.
• It is mainly made of calcium phosphate.
  

Additional information:

• Incisors (8) – used for cutting food
• Canines (4) – used for tearing food
• Premolars (8) – help crush and grind food
• Molars (12) – grind food during chewing
• Total adult teeth = 32

Last verified on 13-03-2026

Explanation

• Digestion specifically means the mechanical and chemical breakdown of food into simpler substances.
• Mechanical digestion includes chewing and churning, while chemical digestion involves enzymes and acids.

Additional information:
Main 5 processes of the digestive system:

1. Ingestion – taking food into the body
2. Digestion – mechanical and chemical breakdown of food
3. Absorption – nutrients enter blood through the intestine
4. Assimilation – cells use absorbed nutrients
5. Egestion – removal of undigested waste

Last verified on 13-03-2026

Explanation

• The alimentary canal wall is made of four main tissue layers that help in digestion and movement of food.
• These layers include mucosa, submucosa, muscular layer, and serosa.
• Secretin is not a tissue layer; it is a digestive hormone released by the small intestine.

Last verified on 13-03-2026

Explanation

• The spleen is not part of the digestive tract; it is part of the lymphatic system and helps in blood filtration and immune response.

Additional information:

Main components of human digestive tract:

• Mouth – ingestion and initial digestion
• Oesophagus – food passage
• Stomach – protein digestion
• Small intestine – nutrient absorption
• Large intestine / Colon – water absorption and feces formation

Last verified on 13-03-2026

Explanation

• Hydrochloric acid (HCl) is produced in the stomach, not the liver.
• The Right lobe, Hepatocyte, Common bile duct are directly associated with the liver.
• The liver is involved in bile production, metabolism, and detoxification.

Last verified on 13-03-2026

Explanation

• Filtration is not part of digestion; it occurs mainly in the kidneys for removing waste from blood.

Additional information:

Main functions of the digestive system:

1. Ingestion – taking in food
2. Propulsion – swallowing and peristalsis
3. Mechanical processing – chewing and churning
4. Chemical digestion – breaking down molecules with enzymes
5. Absorption – nutrients absorbed into blood or lymph

Last verified on 13-03-2026

Explanation

• Human Kidney organs are bean-shaped structures in the body.
• They are located on both sides of the spine in the lower back region.
• Kidneys filter waste products and extra water from blood to form urine.
• A healthy adult normally has two kidneys.

Last verified on 10-03-2026