describe the properties of muscle tissues
Bio 40 A LAB 8A: Muscle Histology and Skeletal Muscles Max: 24 points
Objectives: After successful completion of this Lab activities, the Students should be able to
describe the properties of muscle tissues
identify, compare and contrast the three types of muscle tissues from microscopic observation
conceptualize the organization of muscle (connective tissue wraps and ultrastructure)
Connect the names of skeletal muscles to the word roots
Conceptualize the physiology of muscle contractions and fatigue
Activity 1: Briefly Describe Properties of Muscles: (NOT the functions of muscles)
Properties of muscle tissues
Excitability (= irritability)
Activity 2: Muscle Tissue Histology: This week we will be examining the three types of muscle
tissue: skeletal muscle, cardiac muscle and smooth muscle.
Muscles are composed of many muscle cells that are also called muscle fibers. Skeletal and cardiac muscles are
classified as striated muscles because their muscle fibers have the appearance of altering light and dark bands
under the light microscope.
A. Most skeletal muscles are attached to the bones of the skeleton, enabling them to control body movement.
Skeletal muscle cells are long, cylindrical, multinucleate, nuclei are located on the periphery of the cell.
Skeletal muscle is striated. They have an alternating pattern of light (I) and dark (A) bands.
B. Cardiac muscle is found only in the heart and is responsible for pumping blood through the circulatory system.
Cardiac muscle is striated, but its cells are short, (mostly) uninucleate and branched. One special feature,
intercalated discs, represents the gap junctions (facilitate coordinated/synchronized contraction of cardiac
C. Smooth muscle is the primary muscle surrounding internal organs such as the stomach, urinary bladder, and
blood vessels. Smooth muscle fibers are spindle shaped. That is they are wide in the middle and narrow to
almost pointed at both ends. Smooth muscle cells have a single centrally located nucleus. Smooth muscle cells
do not have visible striations although they do contain the same contractile proteins as skeletal and cardiac
muscle, these proteins are just laid out in a different pattern. Smooth muscle contracts with less tension, but
over a greater range of lengths than skeletal muscle. In addition, it has slow contractions, but with more
control over contraction strength than with skeletal muscle.
Visit the link (https://histologyguide.com/slidebox/04-muscle-tissue.html) to observe the slides and draw
longitudinal sections of each of the three types of muscle tissue under high power (40X) magnification.
Skeletal muscle tissue
Cardiac muscle tissue
Smooth muscle tissue
MH 055ahr Skeletal Muscle
MH 054 Cardiac Muscle
MH 016x Small Intestine
Activity 3: Identify the CT sheaths of skeletal muscle and establish structure-function relationship
Structures for identification
Fascicle wrapped by perimysium
Muscle cell (myofiber)
Activity 4: Ultrastructure of skeletal muscle – the components and changes during contraction 2 points
Skeletal muscle cells contain myofibrils composed of longitudinal arrays of sarcomeres. appear as
alternating dArk and lIght bands (i.e., striated).
The figure A illustrates a portion of a myofibril in relaxed state. Identify the parts indicated by a leader
line. The figure B represents the segment of the myofibril when contracted.
Does it shorten/narrow when
the muscle contracts?
Activity 5: Terms used to Name Skeletal Muscles
Action of the
muscle on body
Great, Large, Vast
4-sided, opposite sides parallel
Long and round
slanted or angled arrangement
Moving a part toward midline
Moving a part away from a midline
Bends a part
Straightens a part
Tightens a part
Three (tri) heads (ceps)
Two (bi) heads (ceps)
Two (di) bellies (gastric)
Name muscles with these roots
Attached to the sternum (sterno),
the clavicle (cleido), and the
Between (inter) the ribs (Costal)
lower leg region
moves the fingers
5.1: Give the reasons the following muscles were given their names. For skeletal muscles with multi-word
names, identify characteristic(s) (two or three) of the muscleâ€™s name.
Extensor carpi ulnaris muscle
External oblique muscle
Rectus abdominis muscle
Zygomaticus major muscle
Orbicularis oris muscle
extensor hallucis longus
Activity 6: Fatigue in isolated skeletal muscle (Virtual Lab)
6 + 3 = 9 points
An elite athlete can run 100 m in 10s; naively one might imagine that the same athlete could run
1000 m in 10 x 10 = 100 s but in fact the world record is around 130 s. Similarly over 10,000 m the
world record is not 1000 s but about 1600 s! Muscle contraction is a complex chain of events.
Video (: https://www.youtube.com/watch?v=R-SSrJMSmlk
1. To understand the terms stimulus frequency, complete (fused) tetanus, fatigue and rest period.
2. To observe the development of skeletal muscle fatigue.
3. To understand how the length of intervening rest periods determines the onset of fatigue.
Visit the link below to complete the following tasks:
A. Pre-lab quiz (4 MC questions) – donâ€™t forget to record response (click on submit)
B. Complete the experiments following defined prompt (donâ€™t forget to record response (click on
â€¢ Take a screenshot of the recorded Experiment Data tables and graphs and the final page
C. Answer the following Review questions.
1. Define muscle fatigue.
2. Predict factors that modify fatigue in Physically Active Individuals. (For reference: https://
3. Sometimes, when hiking in your favorite park, you find, even if you are not very fit, you
can hike for 6-10 hours. However, if you tried to lift a 100 pound (45 kg) barbells
repeatedly, you would rapidly get tired within 5-30 reps over a couple minutes depending
on your athletic ability. Why is the time scale of fatigue so different in these two activities?
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