Human Body Systems HBS PLTW 1.2.2 WCHS Mr. Alasti

Physiatrist

A medical doctor trained in the specialty of physical medicine and rehabilitation. They diagnose illnesses, design treatment protocols, and prescribe medications. They design exercise programs tailored to the patient’s needs and outline a plan of care that physical therapists use

What is a pulled muscle?

A muscle strain. A strain occurs when muscle fibers are under such strong mechanical stress that they are overstretched and can even tear 

Endomysium

A delicate, thin layer of connective tissue that surrounds each individual muscle fiber in skeletal muscle 

Epimysium

The dense connective tissue that surrounds the entire muscle 

Fascicle

A small bundle of fibers wrapped in connective tissue, like a tiny rope made of smaller strings

Perimysium

A connective tissue sheath that surrounds individual muscle fascicles, and separates them from other fascicles within the skeletal muscle

Myofibril

A long, cylindrical organelle within muscle fibers made of repeating protein filaments, primarily actin and myosin, that slide past each other to generate force and produce muscle contraction

Label the image

1. Bone

2. Tendon

3. Muscle

4. Fascicle

5. Sarcolemma

6. Sarcoplasmic Reticulum

7. Myofibril

Label the image

1. Epimysium

2. Muscle Fiber

3. Perimysium

4. Endomysium

5. Blood Vessels

Where are sarcomeres within our drawings?

Within the myofibrils

What are the six muscle rules?

1. Muscles must have a minimum of 2 attachment points and must cross at least 1 joint

2. Muscles always pull and get shorter (they can’t get longer)

3. An attachment more movable is called the insertion, and the attachment that remains stationary is called the origin (the superior, proximal, or medical part is typically the origin, while the distal, inferior, or lateral part is typically the insertion)

4. Muscles that decrease the angle between ventral surfaces of the body are known as flexors, while muscles that increase the angle between ventral surfaces of the body are known as extensors

5. Muscles work in opposing pairs

6. Muscle striations point to the attachment and show the direction of the pull

For smooth movements to occur, can both extensors and flexors be contracting at the same time?

Yes

Medial head of the triceps 

Origin: Proximal half of the dorsal humerus

Insertion: Distal to the elbow on the ulna

Action: Extends elbow

Pectoralis Minor

Origin: Anterior surface of ribs 3-5

Insertion: Coracoid process of the scapula

Action: Stabilizes the scapula by pulling it forward and downward

Clavicular head

Origin: The medial half of the inferior edge of the clavicle

Insertion: Lateral edge of the proximal humerus, inferior to the insertion of the sternal head

Action: Flexes the humerus and helps with the medial rotation of the humerus

Sternocostalis head

Origin: Ribs 1-5 on the lateral edge of the sternum

Insertion: Lateral edge of the humerus, inferior to the insertion of the abdominal head

Action: Draws your forelimb medially (from lateral to medial)

Abdominal head of the pectoralis minor

Origin: Ribs 5-7 (actually attaches to the fascia of the abdominal muscles)

Insertion: Lateral edge of the most proximal part of the humerus

Action: Allows spiking motion- draws the arm up to medial 

External intercostals

Origin: Lateral surface of ribs 1-8

Insertion: Medial border of the scapula

Action: Increase the chest cavity, allowing air to rush in

Brachealis

Origin: Halfway down the humerus

Insertion: Proximal ulna

Action: Flexes elbow