Lecture 4: Muscle and Nerve Tissue

Muscle Tissue L&F

Composed of elongated cells that use ATP hydrolysis to create force, important for body movement, posture, and heat generation

Skeletal Muscle L&F

Striated appearance, voluntary control (except in posture maintenance), attached to bones by tendons, important for movement, posture, heat production, protection

Myofibrils L&F

Myofibrils are responsible for striations, composed of thick filaments (Myosin), and thin filaments (actin), they are arranged in sarcomeres which are the units for myofibrils

Sarcomere Structure

Z disc - Seperate sarcomeres

A band - Dark area with all thick filaments present

I band - Light area with thin filaments only

H zone - Thick filaments only

M Line - Middle line and anchors thick filaments

Epimysium L&F

Surronds entire muscle

Perimysium

Surronds ofascicles

Endomyosium

Surronds individual muscle fibres

Sarcoplasm

Cytoplasm of muscle cells

Sarcoplemma

Plasma membrane of muscle cells

Cardiac Muscle L&F

Striated and branched, single nucleus, interrelated discs join fibres end to end, has involuntary control, and conducts oeletrical impulses though purkinje fibres

Smooth Muscle L&F

Non-striated, spindle shaped, single nucleus, thin filaments attach to dense bodies which is good for contracting a tubular structure, involuntary control, found in skin, BV, intestines

Nervous System Groupings

1. Sensory - Detection of stimuli then alert CNS

2. Integrative - Analysis and storing of info

3. Motor - Effector in response too stimuli through PNS

Axon L&F

Carry the nerve impulse away from neuron, and outputs the impulse

Dendrites L&F

The receiving/input part of the neuron

Multipolar Neuron L&F

Has 2 or more dendrites, one axon, most common neuron in CNS, all motor neurons are multipolar

Bipolar Neurons L&F

Has a dendrite process then an axon process (one axon), cell body between axon and dendrites, found in special sense organs

Unipolar Neurons L&F

Dendrites and axon are continuous, cell body hanging to one side, most sensory nerves are unipolar

Anaxonic Neurons L&F

Cannot distinguish between dendrites and axon, found in brain and special sense organs

CNS Neuroglia - Astrocytes L&F

Star shaped, maintains blood-brain barrier, communicates via gliotransmitters, maintains environment around neurons e.g regulating ions

CNS Neuroglia - Oligodendrocytes L&F

Forms insulating myelin sheet around CNS axons

CNS Neuroglia - Microglia L&F

Phagocytic, helps protect

CNS Neuroglia - Ependymal Cells L&F

Produces CSF, have cilia (flow), microvilli (sampling), moves nutrients and waste, they line the CSF filled ventricles in brain and central Canal of spinal cord

PNS Neuroglia - Schwann Cells L&F

Forms insulating myelin sheet around axons, but only one Schwann cell per axon

PNS Neuroglia - Satellite Cells L&F

Surronds neuron cell bodies, supports and helps fluid exchange