4.3-4 Muscular + Nervous Tissue

Question 1

Muscular Tissue Characteristics

Answer 1

• Called muscle fibers because they are long
• contain actin and myosin - contractile proteins
• 3 types: skeletal, smooth, cardiac

Question 2

Skeletal Muscle

Answer 2

• voluntary
• attached by tendons to bone
• cylindrical shape and long
• multiple nuclei
• fibers appear striated (lines- from placement of actin and myosin)
• contraction causes movement of body parts

Question 3

Smooth muscle

Answer 3

• also called visceral
• found in walls of hollow organs (viscera)
• spindle shaped cells with one nucleus
• involuntary
• no striations
• contracts in wavelike motion
• involuntary - but nervous and endocrine system can modify it

Question 4

Cardiac muscle

Answer 4

• involuntary
• striations
• pumps blood
• can also be modified by nervous and endocrine system
• single and central nucleus
• cells are bound together by intercalated disks
• cell is branched shaped

Question 5

Nervous tissue characteristics

Answer 5

• Found in brain and spinal cord
• neurons: dendrite; cell body; axon (axon forms tract in brain and SC)

Question 6

Neuroglia

Answer 6

• Nourish and support neurons; more numerous
• 4 kinds in the brain
  Microglia - engulf bacteria and cellular debris
  Astrocytes - provide nutrients to neurons
  Oligodendrocytes - form myelin
  Ependymal Cells - line the ventricles, cavities in the brain

Question 7

Schwann cells

Answer 7

• neuroglia outside the brain or SC
• produce myelin sheath- covers nerve fibers with gaps called nodes of ranvier
• myelin sheath speeds electrical signals