Human Body Systems. Body Organization and Homeostasis

Transcription

1 Human Body Systems Body Organization and Homeostasis

2 Objectives Describe how the human body is organized Explain homeostasis

3 Organization of the Body Every cell in the human body is both an independent unit and an interdependent part of a larger community (the entire organism) In other words, each cell is its own living thing, but each cell works with other cells in order to maintain a larger, more complex organism

4 Organization of the Body The levels of organization in a multicellular organism include: Cells Tissues Organs Organ systems

5 Cells A cell is the basic unit of structure and function in living things Specialized cells perform a particular function

6 Tissues A tissue is a group of cells that perform a single function There are 4 basic types: Epithelial tissue includes glands and tissues that cover interior and exterior body surfaces Connective tissue provides support for the body and connects its parts Nervous tissue transmits nerve impulses throughout the body Muscle tissue works with bones to enable the body to move

7 Tissues

8 An organ is a group of tissues that work together to perform a single function For example, in the eye, epithelial tissue, nervous tissue, muscle tissue, and connective tissue all work together for a single function - sight Organs

9 Organ Systems An organ system is a group of organs that perform closely related functions Example: the brain is an organ in the nervous system

10 Nervous System Brain, spinal cord, peripheral nerves Recognizes and coordinates the body s response to changes in its internal and external environments

11 Integumentary System Skin, hair, nails, sweat and oil glands Serves as a barrier against infection and injury Helps to regulate body temperature Provides protection against the sun s UV rays

12 Skeletal System Bones, cartilage, ligaments, tendons Supports the body Protects internal organs Allows movement Stores mineral reserves Provides a site for blood cell formation

13 Muscular System Skeletal muscle, smooth muscle, cardiac muscle Works with skeletal system to produce voluntary movement Helps to circulate blood and move food through the digestive system

14 Circulatory System Heart, blood vessels, blood Brings oxygen, nutrients, and hormones to cells Fights infection Removes cell wastes Helps to regulate body temperature

15 Respiratory System Nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs Provides oxygen needed for cellular respiration and removes excess carbon dioxide from the body

16 Mouth, pharynx, esophagus, stomach, small and large intestines, rectum Converts foods into simpler molecules that can be used by cells of the body Absorbs food Eliminates wastes Digestive System

17 Excretory System Skin, lungs, kidneys, ureters, urinary bladder, urethra Eliminates waste products from the body in ways that maintain homeostasis

18 Endocrine System Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries (in females), testes (in males) Controls growth, development, and metabolism Maintains homeostasis

19 Reproductive System Testes, epididymis, vans deferens, urethra, and penis (males) Ovaries, Fallopian tubes, uterus, and vagina (females) Produces reproductive cells In females, nurtures and protects developing embryo

20 Lymphatic/Immune System White blood cells, thymus, spleen, lymph nodes, lymph vessels Helps protect the body from disease Collects fluid lost from blood vessels and returns the fluid to the circulatory system

21 Homeostasis Homeostasis means keeping things in balance Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in external environments Feedback inhibition is the process in which a stimulus produces a response that opposes the original stimulus To maintain homeostasis, all of the organ systems must be integrated at all times For example, if the nerves sense that the temperature drops, the brain sends signals to the body to increase cell activity, which produces heat to increase the body s temperature

22 Review Questions What are the levels of organization in the human body from smallest to largest? Cells, tissues, organs, and organ systems What is homeostasis? Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in external environments