[PSY4311 - FINALS] Chapter 8: Muscular System

Skeletal Muscle

Voluntary muscles attached to bones, enabling movement. They are under conscious control

Cardiac Muscle

Involuntary muscles found in the heart, responsible for pumping blood automatically.

Smooth Muscle

Involuntary muscles located in organs (e.g., stomach), controlling functions like digestion.

Skeletal Muscle

Voluntary and striated muscles

Cardiac Muscle

Involutary and striated muscles

Smooth Muscle

Involuntary and nonstriated

Smooth Muscle

It can stretch significantly while still being able to contract, which is crucial for organs that change size, like the bladder.

Smooth Muscle

The muscle fibers of this muscle are spindle-shaped and contains a single, centrally located nucleus

Sacromeres

Smooth muscle lacks ____ that contributes to its non-striated apperance

Skeletal Muscle

Long cylindrical fibers with multiple nuclei and striations

Cardiac Muscle

Branched fibers with intercalated discs, one nucleus, and striations

Origin

Fixed attachment point of the muscles

Insertion

The movable attachment point of the muscles

30

Muscle mass begins to decline around age ___, and is often replaced by fat and connective tissue

Rectus

Parallel to midline

Maximus

Largest

Flexor

Decreases joint angle

Biceps

Two origins

Triceps

Three origins

Quadriceps

Four origins

CN VII: Facial Nerve

Facial muscles are primarily innervated by which cranial nerve?

Orbicularis Oris

This muscle originates from the zygomatic bone and inserts into the skin at the corner of the mouth.

Orbicularis Oris

It is responsible for actions such as smiling, kissing, and shaping lips during speech.

Zygomaticus Major

Draws the angle of the mouth upward and outward, facilitating smiling and laughing

Zygomaticus Major

This muscle originates from the zygomatic bone and inserts into the skin at the angle of the mouth.

Buccinator

This muscle originates from the maxilla and mandible, inserting into the obicularis oris

Buccinator

It presses the cheeks against the teeth, aiding in mastication and whistling.

Platysma

A broad muscle that draw the lower lip downward and backward, contributing to expressions of surprise or sadness

Platysma

This muscle originates from the fascia over the deltoid and pectoralis major muscles

Obicularis Oculi

Encircles the eye, responsible for closing the eyelids and blinking

Obicularis Oculi

This muscle originates from the medial wall of the orbit

CN V: Trigeminal Nerve

Mandibular muscles are innervated by which cranial nerve?

Masseter

This muscle originates from the maxilla and zygomatic arch, inserting into the mandible

Masseter

It elevates the mandible, crucial for closing the mouth during chewing.

Temporalis

This muscle originates from the temporal bone and inserts into the mandible

Temporalis

It elevates and retracts the mandible, allowing for powerful biting.

Innate immunity

Type of immunity that is present at birth, hence, provides immediate general protection against pathogens