SYSTEMS OF THE NUTRITION FUNCTION

SYSTEMS OF THE NUTRITION FUNCTION

UNITS 3 AND 4

THE DIGESTIVE SYSTEM

1. ANATOMY OF THE DIGESTIVE SYSTEM

• The digestive tract is a long tube made up of the mouth, pharynx, oesophagus, stomach, small intestine and large intestine.
• The digestive glands secrete substances into the digestive tract.

THE DIGESTIVE ORGANS AND GLANDS

THE salivary glands

• Secrete saliva into the mouth
• There are three pairs

THE DIGESTIVE ORGANS AND GLANDS

THE LIVER

• It produces bile
• The bile is stored into the gallbladder before being released into the duodenum

THE PANCREAS

• It secretes pancreatic juice and releases it into the duodenum

THE DIGESTIVE ORGANS AND GLANDS

THE gastric glands

• They secrete gastric juice and protective mucus

THE INTESTINAL GLANDS

• They secrete intestinal juice and protective mucus

2. digestion

MECHANICAL DIGESTION

Mastication and insalivation

• The teeth tear and grind up the food and the tongue helps to mimx it with the saliva
• The mixture of ground up food and saliva forms a bolus

DEGLUTITION

• The tongue moves the bolus through the pharynx and then to the stomach by peristaltic movements

chemical DIGESTION

ABSORPTION

HOW ASORPTION IS CARRIED OUT

• Most organic nutrients are asorbed in the small intestine by intestinal villi
• In the large intestine water and minerals continue to be abosrbed and faeces are formed. In this portion of intestine live intestinal flora, bacteria that descompose food which has not been digested and they synthesise amino acids and vitamins

Defecation

• Faeces formed in the large intestine are waste products which the body cannot digest and, therefore, cannot absorb.
• After defection reflex faeces are expelled throug the anus.

THE RESPIRATORY SYSTEM

1. ANATOMY OF THE RESPIRATORY SYSTEM

• The respiratory tract is a network of tubes which carry air to the lungs.
• It is made up of the nasal passages, the pharynx, the larynx and the trachea which splits into two bronchi which branch out into bronchioles. The bronchioles end in sacs called the pulmonary alveoli

2. how the respiratory system works

THE CIRCULATORY SYSTEM

1. blood vessels

ARTERIESThey are thick and elastic

1. blood vessels

VEINSThey have valves to prevent reverse blood flow

1. blood vessels

CAPILLARIESThey are very thin which connect the arteries with the veins

2. blood

Functions of the blood

• Transporting substances.
• Defending the body.
• Regulating body temperature.

2. blood

The components of blood

2. blood

The components of blood

3. the heart

Inside the heart

In the right half

In the left half

4. THE CARDIAC CYCLE

5. BLOod FLOW

PULMONARY CIRCUIT1. Blood leaves the right ventricle through the pulmonary artery. 2. After gas exchange has taken place in the lungs, the oxygenated blood returns to the left atrium through pulmonary veins.

SYSTEMIC CIRCUIT3. Blood leaves the left ventricle through the aorta. 4. Blood reaches all organs and tissues through the capillaries. 5. Once substance exchange has taken place in the tissues, the blood returns through the veins. These come together to form the superior and inferior venae cavae, which flow into the right atrium.

THE LyMPHATIC SYSTEM

1. THE INTERNAL ENVIRONMENT

• Blood
• Interstitial fluid: surrounds the cells and directly exchanges with them substances that they need and produce
• Lymph: is a clear liquid which forms from the interstitial fluid. It circulates through the lymphatic system

2. the limphatic system

Lymph capillaries: are very small tubes Lymph vessels: are similar to veins. They collect lymph from the capillaries and flow into the blood circulatory system Lymph nodes: are found along the lymph vessels. They filter lymph and produce white blood cells

THE EXCRETORY SYSTEM

1. ANATOMY OF THE EXCRETORY SYTEM

1. ANATOMY OF THE EXCRETORY SYTEM

Bowman´s capsule

NEPHRONS

Glomerulus

Renal tubule

Collecting duct

2. URINE FORMATION

Filtration

Reabsorption

3. Excretory organs

The lungs: which expel carbon dioxide produce during celular respiration The sweat galnds: sweat is similar to diluted urine and is produced by filtering the blood in the capillaries which are close these glands The liver: It acts as an excretory organ of some substances