Section 1 Flashcards
What type of organs are muscles?
Contractile organs. Through muscle contraction, these organs can perform a number of important functions such as movement
What are the three types of muscle and how do they differ? (how are they controlled, etc)
- Skeletal muscle:
- help the human body move
- most skeletal muscle is attached to bones via tendons - Cardiac muscle:
- found in the heart
- contracts rhythmically, and is modulated by neural activity and hormones - Smooth muscle:
- controlled by the nervous system or hormones
- may be either generally inactive and then respond to stimulation, or it may be rhythmic
How are muscles usually characterized?
Based on their morphology (form) or how they function
What can muscles be categorized morphologically as?
Either striated or smooth muscle
What is striated muscle?
- marked by both light and dark bands (striations).
- can be found in the heart and skeletal muscles.
- characterized by long muscle fibers (cells) with multiple nuclei which are located peripherally (surface) for skeletal muscle or centrally for cardiac muscle. Cardiac muscle also features intercalated discs (which connect heart muscle cells to each other)
What is smooth muscle?
- found in blood vessels, the digestive system, and other viscera
- each of its cells contains a single centrally located nucleus
- it has fusiform-shaped (spindle-like) cells without striations
What can muscle be categorized functionally as?
Voluntary or involuntary
What is voluntary muscle + an example
- muscle that is consciously controlled in order to perform a specific function, such as the muscles that move the skeleton for walking, reaching, talking, etc.
- the type of muscle that is voluntarily controlled is skeletal muscle, (e.g muscles of the upper limb)
What is involuntary muscle?
- not consciously controlled
- consists of smooth muscle and cardiac muscle
- an example is the muscles of the intestines (smooth) and the heart (cardiac)
Which of the following muscles are striated, and why?
a) cardiac
b) smooth
c) skeletal
skeletal and cardiac
due to the banding pattern of the thick and thin filaments that make up the sarcomeres
smooth muscle isn’t arranged into sarcomeres
What is the difference between uni/binucleated?
Uninucleated - has only one nuclei
Binucleated - two nuclei
Name if each of the following is uninucleated, binucleated, and/or multinucleated
a) Skeletal muscle
b) Cardiac muscle
c) Smooth muscle
a) multinucleated
b) uni/binucleated
c) uninucleated
Describe the difference in the shape of each of the types of muscle
Skeletal:
- long and cylindrical/rod like
Cardiac:
- small and branched
- comes into contact with several other cells at the branching points
Smooth:
- fusiform in shape (meaning its wide in the middle, and tapers off at the ends)
Where are each of the types of muscles located in the body?
Skeletal:
- attached to bones (act as levers for bones)
Cardiac:
- found within the heart
Smooth:
- on the walls of all our hollow organs (such as stomach, esophagus, intestines, and most of our blood vessels)
How is each muscle type regulated? (Voluntary/Involuntary)
Skeletal:
- Voluntary
Cardiac:
- Involuntary
Smooth:
- Involuntary
