Musculoskeletal system Flashcards
Define the following words from the musculoskeletal system
Latent period
Twitch
Tetany
Muscle tone (tonus)
Latent period: Lag between stimulation of a muscle and its response
Twitch: Single, very short contraction
Tetany: Sustained contraction, that lacks even partial relaxation
Muscle tone (tonus): A degree of sustained contraction that is always occuring
What is the pacemaker of the heart?
The sinoatrial node (SA node), contains specialized cells in the right atrium, which initiate the contractions of the heart
What are two forms of smooth muscle?
- Separate fibrillary fibres (eg. iris, blood vessels)
- Sheets (visceral muscle - eg bladder, uterus, peristalsis)
Describe modulation of visceral muscle activity?
Visceral muscle contraction is involuntary and rhythmic. Hormones, local metabolites and the autonomic nervous system control it.
The parasympathetic nervous system activates it, and the sympathetic nervous system inhibits activity.
What is a synctium?
A mass of cells which merge and can function together.
Skeletal muscles can merge into synctiums
What is the movable and immovable end of a muscle?
Movable: The insertion
Immovable: The origin
When a muscle contracts, its insertion moves towards the origin
What is abduction and adduction?
Abduction: Movement away from the midline of the body
Adduction: Movement towards the midline of the body
What is a motor unit?
One motor neuron and its many muscle fibres
What are four functions of bones?
- Acting like levers to aid body movement
- Storing inorganic salts (ie. Ca, phosphorous, Na and Mg
- Production of blood cells in red marrow
- Storing fat cells in yellow tissue
What are the four classes of bones?
- Long bones
- Short bones
- Flat bones
- Irregular bones
What is the epiphysis?
The expanded end of a long bone
Contains spongy bone and is surrounded by the periosteum
What is another name for the ‘shaft’ of a bone?
Diaphysis
Primarily composed of compact bone
Describe the two types of bone growth
Membranous bone: Layers of membranous connective tissue appear
Cartilaginous (or endochondral) bone: Cartilage appears and is then replaced by bone
What are epiphyseal growth plates?
Detected in children on x-ray, this plate is a disk of cartilage between the epiphysis (end of a long bone) and diaphysis (where bone is being actively deposited/ossification)
True or false? Joints can be immovable
True
They can be:
- Immovable
- Partly movable
- Freely movable
What are ligaments?
Attachments between bones (bone-bone)
They are formed by dense bands of fibrous connective tissue, which reinforce the joint capsule and help to maintain bones in the proper anatomical arrangement
What are tendons?
Connect muscle to bone. They are formed by the densest kind of fibrous connective tissue. Tendons allow muscular forces to be exerted even when the body (or belly) of the muscle is at some distance from the action.
What happens physiologically if vitamin D cannot be converted to active form or if the active form becomes unable to act on its target tissue?
The body’s ability to absorb ingested calcium from the small intestine would be reduced.
At the neuromuscular junction, ACh receptors are located on the:
A. Plasma membrane
B. Sarcolemma
C. Muscle surface
B. Sarcolemma
The sarcolemma is the muscle’s plasma membrane, and this is part of the motor end plate.
Why was the development of striated muscle in arthropods (eg. insects) paramount to their success?
Increased activity
Striated muscle is very efficient at turning potential energy stored in the chemical bonds of glucose into the kinetic energy of muscle contraction. The contractile proteins are packed into dense, regular arrays to maximize power and minimize muscle bulk. Because of this efficiency, vertebrates and insects can afford to have skeletons.
