Summary Contraction of Skeletal Muscle, Excitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction Coupling, Excitation and Contraction of Smooth Muscle

PER 510- HUMAN PHYSIOLOGY

GUYTON & HALL TEXTBOOK OF
MEDICAL PHYSIOLOGY 14TH EDITION
BY JOHN E. HALL and MICHAEL E. HALL




Special Thank You to George E. Haynes
for Preparation of Power Point Slides


Instructor: Michael Campisi CCP
Unit Two: Membrane Physiology, Nerve, and Muscle
Chapter 6: Contraction of Skeletal Muscle
Chapter 7: Excitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction Coupling
Chapter 8: Excitation and Contraction of Smooth Muscle
Additional videos in this presentation thanks to Dr. Eric Strong

, LEARNING OBJECTIVES
BY THE END OF THIS PRESENTATION, THE STUDENT SHOULD BE ABLE TO:

❖ Explain and understand the structure and histology of skeletal, smooth, and cardiac muscle tissue

❖ Explain the detailed macro and ultra microscopic structure of skeletal muscle

❖ Describe the structure and significance of the neuromuscular junction

❖ Describe and comprehend all the events of skeletal muscle excitation-contraction coupling

❖ Explain the detailed macro and ultra microscopic structure of smooth muscle and compare it to skeletal
muscle

❖ Describe and comprehend all the events of smooth muscle contraction

, There are three types of muscle tissue: Skeletal, Cardiac, and Smooth
➢ Skeletal Muscle ➢ Cardiac muscle
➢ muscle is so named because most skeletal muscles move parts ➢ is so named because it forms the heart wall.
of the skeletal system, while a few attach to and move the skin
➢ Like skeletal it is also striated, however, unlike skeletal it
➢ Most skeletal muscles are completely voluntary, that is, the is completely involuntary and autorhythmic.
nerves controlling the contraction, we normally have conscious
control of them. A few are partial voluntary, for example the ➢ It contains numerous gap junctions and desmosome
skeletal muscle that controls breathing called the diaphragm regions called intercalated disks.
and the skeletal muscles that control posture.
-
forces air into longs after holding breath for a While


➢ Skeletal muscle requires a neurotransmitter or ligand to initiate
NOTE: It has been shown that Skeletal muscle internally
the action potential necessary to create the contraction.
Cazt in Sarcoplasmic
stores ALL its calcium ions needed for contraction;
reticular >
- when
while Cardiac muscle stores internally about 75% and
➢ Microscopic examination of skeletal muscle, shown below, Contraction: Cart into depends on external calcium ions by about 25%.
reveals light and dark bands, thus, the description “striated”. Cytosol


Strictions = Striped




Cardiac muscle

, ➢ Smooth muscle

➢ is so named because of its appearance under the microscope.

➢ Smooth muscle is non-striated and shows a smooth uniform appearance with no light and dark
bands. Sympathetic= constriction

Para : dilation
➢ Smooth muscle is Involuntary.

➢ Most require neurotransmitter to activate the contraction, some use endocrine hormones, while a
few are autorhythmic

➢ There are two types of smooth muscle: NOTE: It has been shown that Smooth Multiunit:
muscle stores 0% of its calcium ions composed of discrete, separate
Unitary, also called visceral: internally and totally depends on
single
smooth muscle fibers.
It is found in the walls of most
-



Neuror
external calcium ion infiltration for Examples are -




multiple nerrous affect
visceral organs of the body. It is controls whole
contraction. Multiple fibers in a muscle

arranged in sheets or bundles. Sheet
➢ the ciliary muscle of
the eye
➢ the iris muscle of the
eye
➢ the pilo-erector
muscles that cause
erection of the hairs
on the skin when
stimulated by the
sympathetic nervous
system