BIO 304 . WEEK 2 . THURSDAY . LAB WORKBOOK

Muscle and Nervous Tissue Overview

Three muscle types and the basic neuron, side by side.

Print this page. You will draw your own diagrams from the directions below, then hand-label the structures listed. Drawing by hand is the integrity mechanism for this course.

Part 1 of 2

Anatomy Lab

1A. What you will draw

Muscle and nervous tissue are the two excitable tissues: both can generate and respond to electrical signals. Today you'll draw all three muscle types side by side, then a neuron in its own panel.

Box A. Three muscle types side by side

Directions

Left: Skeletal muscle. Draw long parallel cylindrical fibers with visible cross-striations. Place several nuclei at the edge of each fiber (multinucleate). Label striated, multinucleate, voluntary.
Center: Cardiac muscle. Draw shorter branched cells with cross-striations. Show one or two central nuclei per cell. Show intercalated discs (thick lines at cell junctions). Label striated, branched, intercalated discs, involuntary.
Right: Smooth muscle. Draw spindle-shaped cells with a single central nucleus. No striations. Label non-striated, single nucleus, involuntary.
Under each, list one typical location: skeletal = limb muscles; cardiac = heart only; smooth = walls of hollow organs, blood vessels.

Draw here. Sketch by hand.

Box B. Basic neuron

Directions

Draw a neuron. Cell body (soma) with nucleus. Several short branched dendrites. One long axon. Axon terminals at the end.
Add a myelin sheath wrapping segments of the axon with gaps (nodes of Ranvier) between segments.
Label cell body, dendrite, axon, myelin sheath, node of Ranvier, axon terminal.
Note next to the neuron: nervous tissue function = generate and conduct electrical signals; muscle tissue function = contract in response to signals.

Draw here. Sketch by hand.

1C. Structures to label (13)

After you finish each drawing, label every structure below directly on your sketch.

Skeletal muscle fiber
Cardiac muscle cell
Smooth muscle cell
Cross-striations
Intercalated disc
Multinucleate
Single central nucleus
Cell body (soma)
Dendrite
Axon
Myelin sheath
Node of Ranvier
Axon terminal

Part 2 of 2

Physiology Lab

2A. Muscle comparison table

Fill in the table below comparing the three muscle types. After the table, answer the follow-up questions.

Property	Skeletal	Cardiac	Smooth
Striated?
Number of nuclei per cell
Voluntary or involuntary?
Branched cells?
Has intercalated discs?
Typical location

Intercalated discs contain gap junctions that allow ions to flow between cardiac cells. Explain why this is functionally critical for the heart.

Both skeletal and cardiac muscle are striated. What does that visible pattern tell us about how they generate force? Why does smooth muscle look different even though it also uses actin and myosin?

2B. Synthesis questions

Answer each in 2 to 4 sentences. Use the language from this week's lecture and your drawings as evidence.

1. Damaged skeletal muscle can be partly replaced by satellite cell activation; damaged cardiac muscle is replaced by scar (non-contractile) tissue. Predict the long-term consequences of a heart attack on cardiac function, and contrast with recovery from a torn skeletal muscle.

2. Smooth muscle is found in the wall of the gut and contracts in slow waves (peristalsis). Predict what happens to digestion in a region of gut where the smooth muscle is damaged.

3. Action potentials in neurons travel at speeds up to 100 meters per second in myelinated axons. Predict what happens to signal speed when myelin is damaged (e.g., multiple sclerosis) and what symptoms might result.

3. What to submit

Complete both the Anatomy Lab (your own drawings, hand-labeled, plus the structures list) and the Physiology Lab (activity and synthesis questions). Photograph or scan every page and upload to Canvas before the deadline listed on the schedule. Hand-drawn, hand-labeled work is the integrity mechanism for this course. Typed or AI-generated diagrams are not accepted.