Tissues

1. Tissues Exercise 40

2. Hierarchy of Biology • Animals coordinate body functions into systems • Digestive, circulatory, etc. • These systems are made up of organs • Circulatory system made up of heart, lungs and vessels • Organs are made up of many different types of tissues • Heart- cardiac muscle, connective tissue

3. Hierarchy of Biology • Cells with similar structure and function constitute a tissue • There are 4 different types of tissues in the body: • Epithelial • Connective • Muscular • nervous

4. Epithelial Tissue • Epithelial tissue • Covers the outside of the body and lines organs and cavities within the body • Contains cells that are closely joined with very little material between them • Many types: • Glandular epithelia- secrete or absorb things • Simple epithelia- single layer of cells • Stratified epithelia- mulitple tiers of cells • Can be different shapes- cuboidal, columnar, squamous

5. EPITHELIAL TISSUE Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often located where secretion or active absorption of substances is an important function. A simple columnar epithelium A stratified columnar epithelium A pseudostratified ciliated columnar epithelium Stratified squamous epithelia Cuboidal epithelia Simple squamous epithelia Basement membrane 40 µm Epithelial Tissue

6. Connective Tissue • Functions mainly to bind and support other tissues • Contains sparsely packed cells scattered throughout an extracellular matrix • Matrix is fibers embedded in a liquid or jelly-like foundation • Matrix secreted by the connective tissue cells

7. Connective Tissue • Collagenous fibers- made of collagen, doesn’t stretch, attach flesh to bone • Elastic fibers- long threads of elastin, provide elasticity of tissues • Reticular fibers- highly branched collagen, join connective tissue to other tissues

8. Connective Tissue • Most common ones in vertebrates are: • Loose connective tissue- • Adipose tissue • Fibrous connective tissue • Cartilage • Bone • Blood

9. Connective Tissue • Loose connective tissue- Holds other organs in place • Adipose tissue- Stores fat, insulates the body and stores energy • Blood- Transports substances from one part of the body to the other • Fibrous connective tissue- Forms tendons and ligaments, joins bones and muscles together • Cartilage- Surrounds bones, protects them, supports nose and ears • Bone- Support, strong but not brittle

10. CONNECTIVE TISSUE 100 µm Chondrocytes Collagenous fiber Chondroitin sulfate Elastic fiber 100 µm Cartilage Loose connective tissue Adipose tissue Fibrous connective tissue Fat droplets Nuclei 150 µm 30 µm Blood Bone Central canal Red blood cells White blood cell Osteon Plasma 700 µm 55 µm Connective Tissue

11. Muscle and Nervous Tissue • Composed of long cells called muscle fibers • Capable of contracting when stimulated by nerve signals • Is divided in the vertebrate body into three types: skeletal, cardiac, and smooth • Nervous tissue • Senses stimuli and transmits signals throughout the animal

12. Muscle • Skeletal muscle is responsible for voluntary body movements • Cardiac muscle pumps blood • Smooth muscle moves the walls of internal organs such as the stomach

13. Nervous Tissue • Forms a communication system that rapidly transmits information • The branching neurons of nervous tissue transmit nerve signals that help control body activities • Cell body and extensions • Dendrite- conveys signals toward cell body • Axon- transmits signals away from the cell body

14. Cell body Nucleus Cellextensions Nervous Tissue

15. MUSCLE TISSUE 100 µm Skeletal muscle Multiple nuclei Muscle fiber Sarcomere Cardiac muscle 50 µm Nucleus Intercalated disk Smooth muscle Nucleus Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus 50 µm Muscle and Nervous Tissue