Human Body Systems Overview

Human Body Systems

• The human body is composed of organ systems
• Organ systems are composed of organs
• Organs are composed of tissues
• Tissues are composed of cells

Learning Objectives

• Describe the general and unique characteristics of different organ systems in representative animals
• Analyze and appreciate the functional relationships of different organ systems in ensuring animal survival

Eleven Body Systems

• Nervous System
• Endocrine System
• Lymphatic System
• Circulatory System
• Respiratory System
• Digestive System
• Excretory System
• Skeletal System
• Muscular System
• Integumentary System
• Reproductive System

Circulatory System

• Transports oxygen and nutrients around the body
• Helps get rid of wastes
• Composed of arteries, veins, heart, and blood

The Heart

• Pumps blood throughout the body

Types Of Blood Vessels

Arteries

• Move blood away from the heart
• Have thick, elastic walls made of smooth muscles
• Connected to ventricles in the heart

Veins

• Move blood toward the heart
• Have one-way valves
• Squeezed by skeletal muscles
• Carry oxygen-poor blood with waste materials

Capillaries

• Microscopic blood vessels

• Connect arteries to veins

• Walls are only one cell thick

• Exchange nutrients and oxygen from blood to body cells

• Arteries carry blood away from the heart

• Veins carry blood to the heart

• Capillaries connect arteries and veins, facilitating the exchange of materials

Blood

• Type of cell that carries oxygen
• Composed of plasma, platelets, white blood cells, and red blood cells
• Plasma: 55% of blood, contains water, ions, proteins, nutrients, wastes, and gases
• Platelets (1%): help clot blood
• White blood cells (1%): fight infection
• Red blood cells (44%): transport oxygen

Digestive System Function

• Digestion breaks down food into small molecules for absorption and use by the body

Nutrients

• Substances in food that provide energy and material for cell development, growth, and repair

Major Organs (Digestive System)

• Mouth
• Esophagus
• Stomach
• Small intestine
• Large intestine

Parts of the Digestive System

Esophagus

• Muscular tube connecting the throat to the stomach
• Moves food down by squeezing (peristalsis)

Stomach

• Muscular bag where chemical and mechanical digestion continue
• Food stays ~4 hours, changes to chyme

Small Intestine

• Tube (nearly 7 meters long) where digestive juices from the liver and pancreas are added
• Villi absorb small nutrient molecules
• All chemical and physical digestion ends here

Large Intestine

• Absorbs water from undigested food
• Unabsorbed materials become more solid
• Stores solid wastes (feces)
• Rectum: where solid wastes (feces) are stored
• Anus: release solid wastes (feces)

Respiratory System

• Major Structures: lungs, nose, mouth, trachea
• Functions: moves air into and out of lungs, controls gas exchange between blood and lungs
• Gas exchange in the lungs occurs through diffusion
  • High concentration of oxygen moves from lungs to blood
  • Carbon dioxide moves from blood to lungs

Excretory System

• Removes cellular wastes from blood and the body
• Major Structures: kidneys, urinary bladder, ureters, urethra, skin, lungs

Muscular System

• Function: Movement
• Major Muscle Types:
  • Skeletal: attached to bones for voluntary actions
  • Smooth: found in the digestive tract and blood vessels to move food and blood (involuntary)
  • Cardiac: heart muscle cells (involuntary)
• Skeletal muscles work in opposing pairs
• Muscles can only pull; they cannot push
• Energy is stored in muscles in a chemical called ATP
• Lactic acid is released when muscles are overworked

Skeletal System

• Major Structures: bones and joints
• Functions: protects organs, shapes and supports the body, interacts with skeletal muscles (allows movement), produces blood cells in bone marrow, stores minerals (calcium and phosphorus)

Reproductive System

• Functions: produces gametes (eggs and sperm), allows for the continuation of the species
• Major Structures: ovaries, uterus, and testes and penis

Lymphatic System

• An organ system that is a part of the immune system and is complementary to the circulatory system
• It consists of lymphatic vessels, lymph nodes, lymphoid organs, lymphatic tissue, and lymph

Integumentary System

• Composed of the skin and its appendages
• Acts as a physical barrier between the external and internal environments protecting and maintaining the animal's body.

Endocrine System

• Regulates body activities (temperature, metabolism, development, and reproduction)
• Maintains homeostasis
• Regulates other organ systems
• Major Glands: hypothalamus, pituitary, pancreas, adrenal, thyroid, testes, ovaries

Nervous System

• Major Structures: brain, spinal chord, nerves, sensory organs
• Functions: regulate behavior, maintains homeostasis, regulate other organ systems, controls sensory and motor functions
• Communication center of the body

Explore the intricacies of the human body systems in this quiz. Analyze the roles and relationships of various organ systems such as the circulatory and nervous systems, and understand how they work together to promote survival. Test your knowledge about organs, tissues, and cells in this educational challenge.