Body System Overview

Function: Transports blood, nutrients, gases, and wastes throughout the body.
Components:
- Heart: Pumps blood; divided into four chambers (right atrium, right ventricle, left atrium, left ventricle).
- Blood Vessels:
  - Arteries: Carry oxygenated blood away from the heart.
  - Veins: Return deoxygenated blood to the heart.
  - Capillaries: Site of exchange between blood and tissues.
Blood Composition:
- Plasma: Liquid component; carries cells and nutrients.
- Red Blood Cells: Transport oxygen.
- White Blood Cells: Immune response.
- Platelets: Blood clotting.

Function: Facilitates gas exchange (oxygen in, carbon dioxide out).
Components:
- Nose/Mouth: Entry points for air.
- Trachea: Windpipe; connects throat to lungs.
- Lungs: Main organs; contain alveoli (tiny air sacs) for gas exchange.
- Diaphragm: Muscle that aids in breathing by contracting and relaxing.
Process:
- Inhalation: Diaphragm contracts, air is drawn in.
- Exhalation: Diaphragm relaxes, air is pushed out.

Function: Provides structure, support, and movement to the body.
Components:
- Bones: Rigid structures forming the skeleton; protect organs and store minerals.
- Muscles: Contract to enable movement; types include skeletal (voluntary), smooth (involuntary), and cardiac (heart).
- Joints: Connections between bones; allow for flexibility and movement.
Types of Muscle Contractions:
- Isometric: Muscle tenses but doesn't change length.
- Isotonic: Muscle changes length while contracting (concentric and eccentric).

Function: Coordinates body functions and responses to stimuli.
Components:
- Central Nervous System (CNS): Comprises the brain and spinal cord; processes information.
- Peripheral Nervous System (PNS): Includes all nerves outside the CNS; connects limbs and organs to the CNS.
Neurons:
- Sensory Neurons: Carry signals to the CNS.
- Motor Neurons: Transmit signals from the CNS to muscles.
- Interneurons: Connect neurons within the CNS.
Divisions:
- Somatic: Controls voluntary movements.
- Autonomic: Regulates involuntary functions (sympathetic and parasympathetic systems).

Function: Breaks down food, absorbs nutrients, and eliminates waste.
Components:
- Mouth: Begins digestion (mechanical and chemical).
- Esophagus: Transports food to the stomach.
- Stomach: Secretes acid and enzymes for digestion.
- Small Intestine: Major site for nutrient absorption.
- Large Intestine: Absorbs water and forms waste.
- Accessory Organs:
  - Liver: Produces bile for fat digestion.
  - Pancreas: Produces digestive enzymes and regulates blood sugar.
  - Gallbladder: Stores bile.

Transports blood, nutrients, gases, and wastes throughout the body.
Heart composed of four chambers: right atrium, right ventricle, left atrium, left ventricle; primary organ for pumping blood.
Blood vessels include:
- Arteries carry oxygenated blood away from the heart to tissues.
- Veins return deoxygenated blood to the heart.
- Capillaries serve as the site for nutrient and gas exchange between blood and tissues.
Blood composition consists of:
- Plasma: Liquid component that transports cells and nutrients.
- Red blood cells: Responsible for oxygen transport to tissues.
- White blood cells: Play a crucial role in the immune response.
- Platelets: Essential for blood clotting to prevent bleeding.

Facilitates gas exchange: oxygen intake and carbon dioxide removal.
Components include:
- Nose/Mouth: Main entry points for air, filtering and humidifying it.
- Trachea: Windpipe that connects the throat to the lungs, conducting air.
- Lungs: Main organs for respiration, containing alveoli for gas exchange.
- Diaphragm: Muscle that contracts during inhalation and relaxes during exhalation.
Process of breathing:
- Inhalation involves diaphragm contraction to draw air into the lungs.
- Exhalation occurs as the diaphragm relaxes, pushing air out of the lungs.

Provides structure, support, and movement for the body.
Components include:
- Bones: Rigid structures forming the skeleton, protecting internal organs and storing minerals.
- Muscles: Enable movement through contraction; types are skeletal (voluntary), smooth (involuntary), and cardiac (heart).
- Joints: Connections between bones that allow flexibility and range of motion.
Types of muscle contractions:
- Isometric: Muscle tenses without changing in length.
- Isotonic: Muscle changes length during contraction, which can be concentric (shortening) or eccentric (lengthening).

Coordinates body functions and responses to stimuli.
Components include:
- Central Nervous System (CNS): Comprises the brain and spinal cord, responsible for processing information.
- Peripheral Nervous System (PNS): Includes nerves outside the CNS, connecting limbs and organs to the CNS.
Neurons types:
- Sensory neurons: Carry signals from sensory receptors to the CNS.
- Motor neurons: Transmit signals from the CNS to muscles for action.
- Interneurons: Serve as connectors within the CNS, facilitating communication between neurons.
Divisions of the nervous system:
- Somatic: Controls voluntary muscle movements.
- Autonomic: Regulates involuntary functions, further divided into sympathetic (fight or flight response) and parasympathetic (rest and digest response) systems.

Breaks down food, absorbs nutrients, and eliminates waste.
Main components include:
- Mouth: Initiates digestion through mechanical (chewing) and chemical (enzymes in saliva) processes.
- Esophagus: Transports food from the mouth to the stomach via peristalsis.
- Stomach: Secretes acid and enzymes, continuing the digestion process.
- Small intestine: Primary site for nutrient absorption into the bloodstream.
- Large intestine: Absorbs water and forms waste for elimination.
Accessory organs enhance digestive processes:
- Liver: Produces bile to aid in fat digestion and filtration of blood.
- Pancreas: Produces digestive enzymes and manages blood sugar levels.
- Gallbladder: Stores bile until needed for digestion.