Digestive System Overview

Overview of the Digestive System

The digestive system is a complex process by which the body breaks down and absorbs nutrients from food.

Functions of the Digestive System

• Ingestion: taking food into the body
• Mechanical digestion: breaking down food into smaller pieces
• Chemical digestion: breaking down food into nutrients using enzymes
• Absorption: absorption of nutrients into the bloodstream
• Elimination: removal of waste products from the body

Organs of the Digestive System

• Mouth:
  • Mechanical digestion: teeth break down food into smaller pieces
  • Chemical digestion: salivary enzymes break down carbohydrates
• Esophagus:
  • Muscular tube that transports food to the stomach
  • Peristalsis: wave-like muscle contractions that move food through the esophagus
• Stomach:
  • Mechanical digestion: stomach muscles mix food with stomach acid and enzymes
  • Chemical digestion: stomach acid and enzymes break down proteins and fats
• Small Intestine:
  • Absorption: nutrients are absorbed into the bloodstream through the walls of the small intestine
  • Chemical digestion: enzymes from the pancreas and bile from the liver break down carbohydrates, proteins, and fats
• Liver:
  • Produces bile, which helps break down fats
  • Filters toxins from the blood
• Pancreas:
  • Produces enzymes that break down carbohydrates, proteins, and fats
  • Produces hormones that regulate blood sugar levels
• Large Intestine:
  • Absorption: water and electrolytes are absorbed into the bloodstream
  • Elimination: waste products are prepared for elimination from the body
• Rectum:
  • Stores waste products until they are eliminated from the body
• Anus:
  • Elimination: waste products are eliminated from the body through the anus

Digestive Process

1. Ingestion: food is taken into the mouth
2. Mechanical digestion: food is broken down into smaller pieces by teeth and tongue
3. Chemical digestion: salivary enzymes break down carbohydrates in the mouth
4. Swallowing: food is swallowed and passes through the esophagus into the stomach
5. Gastric digestion: stomach acid and enzymes break down proteins and fats in the stomach
6. Small intestine: nutrients are absorbed into the bloodstream and chemical digestion continues
7. Large intestine: water and electrolytes are absorbed, and waste products are prepared for elimination
8. Elimination: waste products are eliminated from the body through the anus

Overview of the Digestive System

• The digestive system breaks down and absorbs nutrients from food

Functions of the Digestive System

• Ingestion: taking food into the body
• Mechanical digestion: breaking down food into smaller pieces
• Chemical digestion: breaking down food into nutrients using enzymes
• Absorption: absorption of nutrients into the bloodstream
• Elimination: removal of waste products from the body

Organs of the Digestive System

• Mouth
  • Mechanical digestion: teeth break down food into smaller pieces
  • Chemical digestion: salivary enzymes break down carbohydrates
• Esophagus
  • Muscular tube that transports food to the stomach
  • Peristalsis: wave-like muscle contractions that move food through the esophagus
• Stomach
  • Mechanical digestion: stomach muscles mix food with stomach acid and enzymes
  • Chemical digestion: stomach acid and enzymes break down proteins and fats
• Small Intestine
  • Absorption: nutrients are absorbed into the bloodstream through the walls of the small intestine
  • Chemical digestion: enzymes from the pancreas and bile from the liver break down carbohydrates, proteins, and fats
• Liver
  • Produces bile, which helps break down fats
  • Filters toxins from the blood
• Pancreas
  • Produces enzymes that break down carbohydrates, proteins, and fats
  • Produces hormones that regulate blood sugar levels
• Large Intestine
  • Absorption: water and electrolytes are absorbed into the bloodstream
  • Elimination: waste products are prepared for elimination from the body
• Rectum
  • Stores waste products until they are eliminated from the body
• Anus
  • Elimination: waste products are eliminated from the body through the anus

Digestive Process

• Ingestion: food is taken into the mouth
• Mechanical digestion: food is broken down into smaller pieces by teeth and tongue
• Chemical digestion: salivary enzymes break down carbohydrates in the mouth
• Swallowing: food is swallowed and passes through the esophagus into the stomach
• Gastric digestion: stomach acid and enzymes break down proteins and fats in the stomach
• Small intestine: nutrients are absorbed into the bloodstream and chemical digestion continues
• Large intestine: water and electrolytes are absorbed, and waste products are prepared for elimination
• Elimination: waste products are eliminated from the body through the anus

Brain Function

• The brain is the control center of the body, responsible for processing and integrating information from sensory receptors, controlling voluntary movements, and regulating various bodily functions.

Brain Structure

• The brain consists of three main parts: cerebrum, cerebellum, and brainstem.

Cerebrum

• Divided into two hemispheres: left and right.
• Each hemisphere is further divided into four lobes: frontal, parietal, temporal, and occipital.
• Functions of each lobe:
  • Frontal lobe: motor control, decision-making, problem-solving, and language processing.
  • Parietal lobe: sensory processing, spatial awareness, and attention.
  • Temporal lobe: auditory processing, memory, and language comprehension.
  • Occipital lobe: visual processing.

Cerebellum

• Located at the base of the brain.
• Functions: coordinates muscle movements, balance, and posture, and regulates learning and memory of motor skills.

Brainstem

• Connects the cerebrum to the spinal cord.
• Functions: controls automatic functions, such as breathing, heart rate, blood pressure, and body temperature, and regulates consciousness and sleep.

Neurotransmission

• Chemical messengers (neurotransmitters) transmit signals between neurons.
• Types of neurotransmitters:
  • Excitatory: stimulates the next neuron to fire.
  • Inhibitory: reduces the likelihood of the next neuron to fire.
  • Modulatory: influences the strength of synaptic transmission.

Synaptic Plasticity

• The ability of neurons to change and adapt in response to experience.
• Types of synaptic plasticity:
  • Long-term potentiation (LTP): strengthens synaptic connections.
  • Long-term depression (LTD): weakens synaptic connections.

Brain Waves

• Electrical activity in the brain, measured using EEG.
• Types of brain waves:
  • Alpha waves: relaxed, closed eyes.
  • Beta waves: active, focused attention.
  • Theta waves: drowsy, sleep.
  • Delta waves: deep sleep.