The Body's Systems Overview

Study Notes

The Body's Systems

Cells: The basic building blocks of the body, forming tissues.
Tissues: Groups of similar cells that perform a specific function, forming organs.
Organs: Structures composed of different tissues that work together to perform a specific task, and form organ systems.
Organ Systems: Groups of organs that work together to carry out major bodily functions.

Nervous System

Function: Controls actions, thoughts, and feelings; sends instructions to the body.
Components: Brain, nerves.
Brain: Controls both conscious and unconscious actions.
- Conscious Decisions: Actions like moving an arm are controlled by the brain.
- Unconscious Actions: Functions like breathing and digestion operate autonomously.
Nerves: Transmit messages as electrical impulses.

Digestive System

Function: Breaks down food for the body to absorb nutrients.
Components: Mouth, throat, stomach, intestines, liver, gallbladder, pancreas.
Liver: Largest gland in the body, produces bile for digestion.

Urinary System

Function: Filters blood and removes waste products.
Components: Kidneys, bladder, ureter, urethra.
Kidneys: Function like filters to remove waste.

Respiratory System

Function: Takes in oxygen and releases carbon dioxide.
Components: Nose, windpipe, lungs.
Blood: Transports oxygen to the lungs.

Circulatory System

Function: Transports blood, oxygen, nutrients, and waste products throughout the body.
Components: Heart, blood vessels (arteries, veins), lymph vessels.
Heart: Pumps blood through the body.
Arteries: Carry oxygenated blood from the heart to the cells.
Veins: Carry deoxygenated blood back to the heart.
Blood: Purified by the liver and kidneys.

Endocrine System

Function: Produces hormones that regulate various bodily functions.
Components: Glands (e.g., pancreas).
Hormones: Chemical messengers that travel through the blood to target organs, such as estrogen, insulin, adrenaline, and cortisone.

Reproductive Systems

Male Reproductive System: Includes the penis and testes.
Female Reproductive System: Includes the uterus, ovaries, fallopian tubes, and vagina.

The Human Body Systems

Cells: Form tissues, which then make up organs. Each organ has a specific function. Organs work together as organ systems.
Nervous System: Controls actions, thoughts, and feelings. Brain is central, with each side controlling the opposite side of the body.
Nervous System: Communication: Transmits information as electrical impulses. Can control conscious actions (e.g., moving an arm) and unconscious actions (e.g., breathing, digestion).
Digestive System: Breaks down food. Composed of mouth, throat, stomach, intestines, liver, gall bladder, and pancreas.
Liver: Largest gland in the body, produces bile.
Urinary System: Cleanses blood and removes waste. Includes kidneys, bladder, ureters, and urethra. Kidneys act as filters.
Respiratory System: Responsible for breathing. Includes the nose, windpipe, and lungs. The blood carries oxygen to the lungs.
Circulatory System: Consists of the heart, blood vessels (arteries, veins), and lymph vessels.
Blood: Transported by the heart, delivers oxygen and nutrients to cells and takes waste away. Arteries carry blood from the heart; veins return blood back.
Blood Purification: Liver and kidneys purify blood.
Endocrine System: Produces hormones that regulate organ function.
Hormones: Produced by glands, such as the pancreas, and travel through the bloodstream to target organs (examples include estrogen, insulin, adrenaline, and cortisone).
Male Reproductive System: Includes the penis and testes.
Female Reproductive System: Includes the uterus, ovaries, fallopian tubes, and vagina.