Muscles Flashcards
(44 cards)
What are the different connective tissue sheaths of muscles?
- Epimysium
- Perimysium and Fascicles
- Endomysium
Define the term ‘Epimysium’
Epimysium means the outside muscle. It is an overcoat of dense irregular connective tissue that surrounds the whole muscle.
Define the terms ‘Perimysium’ and ‘Fascicles’
Inside each skeletal muscle, muscle fibres are grouped into fascicles, which resemble a bundle of sticks. A layer of fibrous connective tissue, called the Perimysium, surrounds the fascicles.
Define the term ‘Endomysium’
The Endomysium is a wispy sheath of connective tissue that surrounds each individual muscle fibre. It consists of fine areolar tissue.
Define the term ‘Sarcoplasm’
Is the cytoplasm (material within a cell excluding the nucleus of a muscle cell). It contains unusually large amounts of glycosomes and myoglobin.
Define Myofibrils
A single muscle fibre (fascicle), containing heaps of Myofibrils that can run parallel to its length. Myofibrils contain the contractile elements of skeletal muscle cells: Sarcomeres. They in turn contain even smaller rod like structures called myofilaments.
Circular Muscle Fibre
This type of muscle surrounds openings in our body like the mouth. When they contract, they close the opening. Another word for this muscle is a sphincter.
Convergent Muscle Fibre
All muscle fibres and vesicles originate in a broad area and converge onto a single single insertion. So when a muscle fibre contracts, they all pull at a specific point. Eg. Pectoral is Major.
Parallel Muscle Fibre
All fibres and vesicles are arranged in a parallel direction to each other. Straight from point of origin to insertion. Can contract a lot but not strong. Eg. Sartorius in your thigh.
Fusiform muscle fibre
Has a larger middle part. This allows for it to produce more power than a simple parallel muscle fibre. Eg. Biceps Branchii
Uni-pennate Muscle Fibre
This muscle fibre resembles half a feather. It cannot contract much but has a lot of power as it has more muscle fibres.
Bi-pennate Muscle Fibre
Looks like a two feather together. Produces a lot of power. Eg. Rectus Femoris (Thigh).
Multi-pennate muscle fibre
Resembles a bunch of feathers connected at one point. Multiple tendons and vasicles which connect together in one muscle. Massive power. Eg. Deltoid.
What are the three types of muscles?
- Smooth Muscle
- Cardiac Muscle
- Skeletal Muscle
Striations
The columns of light and dark that you see in a skeletal muscle. Contain A bands and I bands.
A Band
The dark columns in striations. Contains proteins Actin and Myosin.
I Bands
The light columns in striations. Only contains the protein Actin.
Sarcomere
The structural unit of a Myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band.
What are the characteristics of muscle tissue?
- Highly Cellular.
- Highly Vascular.
- Contractile.
- Excitability/Responsiveness.
- Extensibility.
- Elasticity.
In what ways can muscles attach to bones?
Direct and Indirect attachments.
What is a direct attachment?
A direct attachment would include the Epimysium directly attaching to the bone.
What is an indirect attachment?
An indirect attachment or fleshy attachment is fused to the perichondrium of a cartilage
What are Myofibrils?
A single muscle fibre (fascicle) contains heaps of Myofibrils that run parallel to its length.
What are Sarcomeres?
The are the contractile elements of a skeletal muscle cell. Contained inside Myofibrils.
