Unit 2 Part 2 Notes -- Tissues

Unit 2 Part 2 – Tissues

1. Tissues

• Epithelial
• Connective
• Muscle
• Nervous

1. Tissues differ from each other in size, shape, amount, kind of material, and function.

2. Epithelial Tissue

• Covers body and parts.
• Packed tightly together with little or no intercellular material (no blood vessels).
• Subdivided according to shape and arrangement of cells

A.  Shape

• Squamous   –  Flat and scale like

• Cuboidal – Cube shaped

• Columnar – Higher than wide

B.  Arrangement

• Simple – Single layer of same shaped cells

• Stratified – Many layers of same shaped cell

• Transitional – Several layers of different shaped cells

C.  Types/Functions of Cell Arrangements

• Simple Squamous

1. Single layer, flat, and scale-like

2. Function – Absorption

3. Ex. Oxygen into blood from lungs

• Stratified Squamous

1. Several layers of closely  packed cells

2. Function – Protection from microorganisms, found in areas of high friction

3. Ex. Skin and mucous membranes

• Stratified Transitional

1. Found in areas needed to stretch

2. Usually ten or more layers (protection) when not stretched

3. When stretching occurs, epithelial sheet expands to form a single layer

4. Ex. Urinary bladder

• Simple Columnar

1. Contain “goblet cells” which produce mucus.

2. Specialize in absorption.

3. Ex. Inner surfaces of stomach, intestines, and parts of respiratory and reproductive tracts.

• Pseudo-stratified

1. Appears to be two layered but actually is not (pseudo – false)

2. Contain cilia --- Movement of particles across surface of cells/tissue

3. Ex. Trachea and windpipe

• Glandular

1. Act alone or in groups (glands).

2. Exocrine glands – Release product into duct. (Tears, Sweat, Saliva, and Oil are examples)

3.                               Endocrine glands – Release product into bloodstream.

3. Connective Tissue

• Most abundant of tissues.

• Resemble paper thin webs that anchor organs together and give them their shape.

• Also exist as strong cords (ligaments and tendons)

• Differ from epithelial tissue in amount and kind of intercellular material (matrix)

• 7 kinds of connective tissue

1. Areolar

   

   1. Most widely distributed.

   2. “Glue” that anchors internal organs.

2. Adipose

   

   1. Specialized to store lipids.

   2. Numerous spaces present between cells so they may swell.

3. Fibrous

   

   1. Consist of bundles of strong, white collagen.

   2. Provide great strength and non-stretchability.

4. Bone

   

   1. Matrix is hard and calcified.

   2. Form numerous building blocks    called Haversian systems.

   3. Storage area for calcium and phosphorus.

   4. Provide protection and support.

5. Cartilage

   
   

   1. Differs from bone in that it resembles plastic or gristle.

   2. Firm but flexible.

6. Blood

   

   1. Liquid matrix

   2. Function – Transportation and Protection

   3. Ex. Red and White blood cells

7. Hemopoetic Tissue

   

   1. Found in marrow of bone, spleen, tonsils, and lymph nodes

   2. Function – Blood cell and Lymphatic cell formation (Rid body of disease)

4. Muscle Tissue

• 3 Types
  1. Skeletal

     
     

     1. Voluntary -can be willfully controlled (controlled by the SNS - Somatic Nervous System)
     2. Individual cells appear long and threadlike.
     3. Attached to bones and create movement.
     4. Striated – has dark bands
     5. Multi-nucleate - more than one nucleus per cell

  
  

  1. Cardiac

     
     

     1. Form walls of the heart.
     2. Involuntary -- Controlled by the ANS - (Autonomic Nervous System)
     3. Striated with intercalated disks
     4. Allows heart to expand and contract (heartbeat)
     5. Shorter and web-like
     6. Uni-nucleate - only one nucleus per cell

  
  

  1. Smooth (Visceral)​

     
     

     1. Form walls of hollow organs (blood vessels, intestines, and respiratory tubes).
     2. Involuntary
     3. Contractions propel food down digestive tract and bronchioles to contract during asthma attacks (Peristalsis)
     4. Non-Striated
     5. Uni-nucleate - only one nucleus per cell

5. Nervous Tissue

• Consist of nerve cells (neurons) and supporting cells (neuroglia)
• Neurons contain 1 axon (carry impulses away from cell body) and 1 or more dendrites (carry impulses to cell body)
• Function – Rapid communication  between body parts.