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Animal Body -
Chapter 23
Animal Body
Human body has 2 million cells at the time of birth and adults have 60-100 trillion cells. These cells
organize into tissues.
There are 4 basic types of tissues: Epithelial, Connective, Muscle and Nerve tissues.
Epithelial Tissues
Epithelial Tissues are surface forming tissues. These can cover external or internal surfaces of body
or organs. These lie on a common basement membrane.
Epithelial tissues may be simple or stratified.
Simple – 1 layered like lining of lungs
Stratified – many layered like the epidermis of skin
Organ-Systems
Tissues organize into organs and organs organize into organ-systems.
There are 11 main organ-systems in human body.
Integumentary - skin, Skeletal, Muscular, Nervous – brain, Sense organs, Endocrine - hormones,
Circulatory – heart and blood, Respiratory – lungs, Digestive – stomach and intestine, Urinary,
Reproduction and Development.
Muscles are specialized tissues for contraction. Sarco = muscle, Sarcolemma = covering of muscle,
muscle fiber = specialized cell formed of hundreds of Myofibrils. 3 kinds of muscle fibers: skeletal,
cardiac and smooth.
Voluntary muscle
Skeletal
Attach directly or indirectly to bones
Involuntary muscles
Cardiac and Smooth
Are present in heart or other visceral organs
Bones and muscles
Human body has 206 bones and more than 600 muscles in it.
Nerve Tissue
Neurons are cells that conduct information in the form of electrical disturbances = Nerve impulses.
These cells are very long.
Recap 1 Animal body
1. Human body has ---types of tissues and ---organ-systems.
2. ----tissues cover surfaces inside or outside body.
3. Blood and bones are types of-----tissue.
4. ---- muscles are voluntary and cardiac muscles are involuntary in nature.
5. ----tissue is formed of special cells – neurons that conduct electric impulses.
6. ----- system has brain, spinal cord and nerves.
7. ----system secretes hormones to regulate body metabolism.
8. We flex our -----by contracting our muscles.
9. There are ----bones in body and more than --- muscles