Human Body Systems: Functions and Diseases
Human Body Systems: Functions & Diseases
Apparatus and Their Functions
| Apparatus | Function |
|---|---|
| Digestive | Responsible for digesting food and converting it into simpler substances (nutrients) (digestion). |
| Respiratory | Provides for the exchange of gases, i.e., oxygen intake and carbon dioxide removal. |
| Circulatory | Transports oxygen and substances throughout the body via the blood. |
| Excretory | Removes waste substances carried by the blood. |
Anatomy of the Digestive System
Digestive Tract: Mouth, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum), and associated glands (salivary glands, liver, pancreas).
- Mouth: Cavity where food enters the digestive tract. Contains the tongue and teeth to chew food. Salivary glands pour saliva into the mouth.
- Liver: Produces bile, which is stored in the gallbladder and released into the duodenum to help dissolve fat.
- Pancreas: Produces pancreatic juice, which is poured into the duodenum to complete digestion.
- Small Intestine: A tube bent in the abdominal cavity where digestion is completed, and nutrient absorption occurs.
- Pharynx: Passageway for food from the mouth to the esophagus.
- Esophagus: Transports food to the stomach through the movement of its walls.
- Stomach: The entry point is called the cardia, and the exit point is the pylorus. Part of digestion occurs here through the secretion of gastric juice.
- Large Intestine: Absorbs water and mineral salts through its walls. Stool is formed here with undigested substances.
The digestive functions allow food to be transformed into nutrients.
Digestive Functions
| Digestive Functions | Description | Location |
|---|---|---|
| Ingestion | Entry of food into the digestive tract | Mouth |
| Digestion: | ||
| Mechanical | Cutting, crushing, and moving food | Mouth and Stomach |
| Chemical | Converting food into nutrients by the action of chemicals | Mouth, Stomach, and Small Intestine |
| Absorption | Nutrients pass through the walls of the digestive tract and enter the blood | Small Intestine and Large Intestine |
| Egestion | Elimination of stool | Large Intestine |
Respiratory System
The respiratory system is responsible for taking in oxygen from the outside air, delivering it to the blood, and removing carbon dioxide.
Airways: Nasal passages, pharynx, larynx, trachea, bronchi, and bronchioles. Lungs (pulmonary alveoli).
- Nostrils: Air enters, is heated, and moistened.
- Trachea: Protected by a series of C-shaped cartilages that prevent it from being crushed.
- Lungs: Inside, gas exchange with the blood occurs.
- Pharynx: Carries air to the larynx.
- Larynx: A short tube that contains the vocal cords.
- Bronchi: Divide into smaller branches called bronchioles, ending in thin-walled sacs called pulmonary alveoli.
Digestive Processes:
- Ingestion of food through the mouth -> Mouth
- Digestion -> Mouth, stomach, and small intestine.
- Absorption -> Small intestine and large intestine.
- Egestion -> Large intestine.
Digestive System Diseases
| Disease | Features | Causes |
|---|---|---|
| Caries | An infectious disease affecting the hard tissues of teeth. | Bacteria that convert carbohydrates into acids. |
| Constipation | A disorder causing difficult evacuation of feces. | Stress, drugs, and diets low in vegetable fiber. |
| Ulcers | Open sores on the inner walls of the digestive tract. | Stress, infection by Helicobacter pylori bacteria. |
| Gastroenteritis | Inflammation of the internal membranes lining the stomach and intestine. | Infection by viruses or bacteria. Causes vomiting, diarrhea, and abdominal discomfort. |
| Liver Cirrhosis | A chronic disease that is a dieback of the liver, causing malfunction. | Excessive alcohol consumption. |
Gas Exchange
Gas exchange occurs in the pulmonary alveoli through diffusion across the membranes of the alveoli and capillaries. Gases pass through the membrane to equalize concentrations on both sides.
Lung Ventilation: The process by which atmospheric air enters the lungs and then exits. It is done by inspiration (air entering the lungs) and expiration (air exiting to the outside). The muscles involved in pulmonary ventilation are the diaphragm and the intercostal muscles.
Respiratory System Diseases
| Disease | Characteristics | Causes |
|---|---|---|
| Bronchitis | Inflammation of the bronchi, causing breathing difficulties. | Bacteria |
| Asthma | Temporary narrowing of the airways. Causes oxygen deficiency in tissues and difficulty breathing. | Allergies, intense physical exercise, or respiratory infections. |
| Tuberculosis | A contagious disease that destroys lung tissue. | Bacteria |
| Cold & Flu | Highly contagious infections of the respiratory tract. | Virus |