IB biology HL notes
TOPIC 6, 11, & OPTION H: HUMAN HEALTH AND PHYSIOLOGY
Digestive System
Includes all the structures that are concerned with bringing food into the body to provide for the needs of the body’s cells.
Each cell in an organism relies on a continuous expenditure of energy. Fats, carbs, and proteins are broken down during cellular metabolism and the energy derived from them is used to make ATP.
The digestive system deals with:
Ingestion, which is the bringing of nutrients into the body.
Mechanical breakdown, which is the breakdown of food into smaller pieces, increasing SA for enzymes to act.
Chemical breakdown, which is when larger polymers are chemically digested into monomers.
Absorption, which is when simple monomers pass out of the digestive tract (gastrointestinal tract) and into cells.
Elimination, which is when material that cannot be digested is expelled.
Digestive anatomy includes: Mouth = entrance to gastrointestinal (GI) tract, contains: teeth- cuts and grinds food to increase its SA to improve the rate of digestive reactions salivary glands- 3 pairs that lubricates food with saliva, containing salivary amylase (breaks starch into disaccharides) and antibacterial enzymes. Saliva dissolves some food. taste buds- identify the type and quality of food. Food dissolves in saliva and moves into the taste pores. Receptor cells sense the taste and pass on the message to attached nerve cells. The more you have, the more sensitive you are to the taste.
tongue- pushes food together into a bolus for swallowing. Pharynx = cavity connecting the mouth and nose to the esophagus and trachea. It is a structure that belongs to both the respiratory and digestive systems. It includes: epiglottis- a flap of skin that prevents food from entering the trachea. Swallowing raises the larynx to meet the epiglottis. It also conducts food down the esophagus. Esophagus = muscular tube that propels food from the mouth to the stomach. Circular muscles
Digestive System
Includes all the structures that are concerned with bringing food into the body to provide for the needs of the body’s cells.
Each cell in an organism relies on a continuous expenditure of energy. Fats, carbs, and proteins are broken down during cellular metabolism and the energy derived from them is used to make ATP.
The digestive system deals with:
Ingestion, which is the bringing of nutrients into the body.
Mechanical breakdown, which is the breakdown of food into smaller pieces, increasing SA for enzymes to act.
Chemical breakdown, which is when larger polymers are chemically digested into monomers.
Absorption, which is when simple monomers pass out of the digestive tract (gastrointestinal tract) and into cells.
Elimination, which is when material that cannot be digested is expelled.
Digestive anatomy includes: Mouth = entrance to gastrointestinal (GI) tract, contains: teeth- cuts and grinds food to increase its SA to improve the rate of digestive reactions salivary glands- 3 pairs that lubricates food with saliva, containing salivary amylase (breaks starch into disaccharides) and antibacterial enzymes. Saliva dissolves some food. taste buds- identify the type and quality of food. Food dissolves in saliva and moves into the taste pores. Receptor cells sense the taste and pass on the message to attached nerve cells. The more you have, the more sensitive you are to the taste.
tongue- pushes food together into a bolus for swallowing. Pharynx = cavity connecting the mouth and nose to the esophagus and trachea. It is a structure that belongs to both the respiratory and digestive systems. It includes: epiglottis- a flap of skin that prevents food from entering the trachea. Swallowing raises the larynx to meet the epiglottis. It also conducts food down the esophagus. Esophagus = muscular tube that propels food from the mouth to the stomach. Circular muscles