Lecture Ten Flashcards
What are the parts of an anatomical lever?
Bone = lever
Joint = fulcrum
Contraction = applied force
Weight of what is being moved = load
What is a first class lever and its purpose in a biological context? What’s an example and what part is what in the lever?
A first class lever has the fulcrum in the middle (between force and load). It stabilizes the joint position. An example of this is neck extension at the atlanto-occipital joint. The head is the load, the muscles in the neck are the applied force, and the joint is the fulcrum.
What is a second class lever and its purpose in a biological context? What’s an example and what part is what in the lever?
A second class lever has the load in the middle (between fulcrum and applied force). This lever is effective at carrying heavy loads. An example of this is plantar flexion at the ankle joint. The toes are the fulcrum, the body weight is the load and the calf muscles are the applied force.
What is a third class lever and its purpose in a biological context? What’s an example and what part is what in the lever?
A third class lever has the applied force in the middle (between fulcrum and load). This lever is good for a large range of movement with speed. An example of this is flexion at the elbow joint. The load is whatever is being lifted, the applied force is the biceps brachii, and the fulcrum is the elbow joint.
How does the length of muscles determine the function?
Muscles can only shorten up to 50%, so if the muscle is short, the ROM will be short, and if the muscle is long, then the ROM will be long.
How does the number of muscle fibres determine the function?
The tension is directly proportional to the cross-sectional area (CSA). The greater the number of fibres, the greater the CSA, the greater the tension and therefore the stronger the muscle.
What are the two muscle fibres arrangements and what makes them different?
Parallel arrangement is when the muscle fibres are arranged vertically, between muscle tendons and attachments. There are less total fibres (so not as powerful+strong), but greater shortening. Pennate arrangement is when the fibres are arranged obliquely between muscle tendons and attachments. There are more fibres total (so more powerful) but lesser shortening, as the muscle can only shorten as much as the shortest muscle. Pennate muscles can also occur as unipennate, dipennate and multipennate.
What are the three types of muscle action and what do they do? Give biological examples.
Concentric, the tension is greater than the load, the muscle shortens (contracts) and there is a change in joint position and angle. An example of this is flexing the biceps brachii. Eccentric, the tension is less than the load. The muscle lengthens, there is a change in joint position and the angle increases. An example of this is elbow extension. Isometric, the tension is equal to the load. There is no change in length or joint position. An example of this would be holding the elbow joint still?
What are the four muscle roles and what do they do?
Agonists, they create movement and act concentrically. Antagonists, they oppose/control movement, and act eccentrically. Stabilisers, they hold the joint still and prevent movement, and work isometrically. Neutralisers, they eliminate unwanted movement from another muscle. For example, you can flex your elbow without supination and pronation.
The concentric action will always be the same based on the muscle’s location in relation to the joint (not including the knee). What are these?
Anterior=flexion
Posterior=extension
Lateral=abduction
Medial=adduction
What is the origin, insertion, and movement of the biceps brachii?
Origin = scapula
Insertion = radial tuberosity
Movement = flexion in the shoulder and elbow, supination in the radioulnar joints
What is the origin, insertion, and movement of the triceps brachii?
Origin = scapula and humerus
Insertion = olecranon process of ulna
Movement = Extension in the shoulder and elbow
What is the origin, insertion, and movement of the deltoid?
Origin = scapula and clavicle (pectoral girdle)
Insertion = deltoid tuberosity (touch it so u know where it is bish)
Movement = abduction, flexion and extension in shoulder (as fibres run in different directions)
What is the origin, insertion, and movement of the iliopsoas?
Origin = iliacus originates from iliac fossa, psoas major originates from lumbar vertebrae
Insertion = both merge and insert at femur
Movement = hip flexion
What is the origin, insertion, and movement of the gluteus maximus?
Origin = ilium and sacrum
Insertion = femur
Movement = hip extension
What is the origin, insertion, and movement of the quadriceps femoris?
Origin = the rectus femoris originates at the ilium. The vastas medialis, intermedius and lateralis originate from the femur.
Insertion = Tibial tuberosity
Movement = rectus femoris does hip flexion. Also makes knee extend. They join right above the knee, forming a tendon which picks up the patella.
What is the origin, insertion, and movement of the hamstrings?
Origin = the semimembranosus and semitendinosus originate at the ischium, and the biceps femoris originates at the femur.
Insertion = The semimembranosus and semitendinosus insert at the tibia, the biceps femoris inserts at the fibula.
Movement = hip extension, knee flexion and rotation when flexed
What is the origin, insertion, and movement of the tibialis anterior?
Origin = tibia
Insertion = tarsals
Movement = dorsiflexion in ankle
What is the origin, insertion, and movement of the triceps surae?
Origin = gastrocnemius originates from condyles of femur, soleus originates from tibia and fibula.
Insertion = they insert at calcaneus via calcaneal/Achilles tendon.
