Anatomy & Physiology Practical Study Guide: Skeleton, Muscles, and Nervous System

Axial Skeleton

Overview of the Axial Skeleton

The axial skeleton forms the central axis of the human body and includes the skull, vertebral column, and thoracic cage. It provides support and protection for the brain, spinal cord, and vital organs within the thorax.

• Axial bones: Include the skull, vertebrae, ribs, and sternum.

• Functions: Protection of vital organs, support for body posture, and attachment for muscles.

• Bone features: Foramina, processes, and sutures are key anatomical landmarks.

• Skull bones: Identify and locate bones such as the frontal, parietal, occipital, temporal, sphenoid, ethmoid, maxilla, mandible, zygomatic, nasal, lacrimal, palatine, vomer, and inferior nasal concha.

• Vertebral column: Includes cervical, thoracic, lumbar, sacral, and coccygeal vertebrae.

• Thoracic cage: Composed of ribs and sternum, protecting the heart and lungs.

• Sinuses: Air-filled spaces in the skull that reduce weight and enhance voice resonance.

Example: The foramen magnum in the occipital bone allows passage of the spinal cord.

Appendicular Skeleton

Overview of the Appendicular Skeleton

The appendicular skeleton consists of the bones of the limbs and girdles, facilitating movement and interaction with the environment.

• Pectoral girdle: Includes the scapula and clavicle.

• Pelvic girdle: Composed of the ilium, ischium, and pubis.

• Upper limb bones: Humerus, radius, ulna, carpals, metacarpals, phalanges.

• Lower limb bones: Femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.

• Bone features: Identify anatomical landmarks such as condyles, tuberosities, and processes.

Example: The olecranon process of the ulna forms the bony prominence of the elbow.

Muscle Physiology Lab

Muscle Physiology Concepts

Muscle physiology explores the mechanisms of muscle contraction, relaxation, and the electrical activity underlying these processes.

• Muscle twitch: A single contraction-relaxation cycle in a muscle fiber.

• Motor unit: A motor neuron and all the muscle fibers it innervates.

• Phases of muscle twitch: Latent period, contraction phase, relaxation phase.

• Summation and tetanus: Increased frequency of stimulation leads to stronger contractions.

• EMG (Electromyography): Measures electrical activity in muscles; voltage readings correlate with muscle activity.

• Recruitment: Activation of additional motor units to increase muscle force.

Equation:

$\text{Force} = \text{Number of active motor units} \times \text{Force per unit}$

Example: During sustained exercise, more motor units are recruited to maintain muscle tension.

Muscles of the Axial and Appendicular Skeleton

Muscle Identification and Function

Muscles are classified by their location, origin, insertion, and action. Understanding these features is essential for identifying muscle groups and their roles in movement.

• Axial muscles: Include sternocleidomastoid, trapezius, temporalis, masseter, and others.

• Appendicular muscles: Include deltoid, biceps brachii, triceps brachii, gluteus maximus, quadriceps, hamstrings, etc.

• Rotator cuff muscles: Supraspinatus, infraspinatus, teres minor, subscapularis.

• Types of movement: Flexion, extension, abduction, adduction, rotation, circumduction.

Example: The biceps brachii flexes the forearm at the elbow joint.

Nervous System

Organization and Function of the Nervous System

The nervous system is divided into the central and peripheral components, responsible for processing and transmitting information throughout the body.

• Central nervous system (CNS): Brain and spinal cord.

• Peripheral nervous system (PNS): Cranial nerves, spinal nerves, and associated ganglia.

• Major brain regions: Cerebrum, cerebellum, diencephalon, brainstem.

• Spinal cord anatomy: Dorsal and ventral roots, gray and white matter, ascending and descending tracts.

• Important structures: Corpus callosum, thalamus, hypothalamus, medulla oblongata, pons, midbrain.

• Cranial nerves: Twelve pairs, each with specific sensory and/or motor functions.

• Spinal nerves: Emerge from the spinal cord and innervate the body.

Example: The brachial plexus is a network of nerves that supplies the upper limb.

HTML Table: Major Bones of the Axial and Appendicular Skeleton

Region	Major Bones	Key Features
Axial Skeleton	Skull, Vertebrae, Ribs, Sternum	Foramina, Processes, Sinuses
Appendicular Skeleton	Scapula, Clavicle, Humerus, Radius, Ulna, Femur, Tibia, Fibula, Pelvis	Condyles, Tuberosities, Epicondyles

HTML Table: Muscle Twitch Phases

Phase	Description
Latent Period	Time between stimulus and onset of contraction
Contraction Phase	Muscle fibers shorten and generate force
Relaxation Phase	Muscle tension decreases and fibers return to resting length

HTML Table: Major Brain Regions and Functions

Region	Function
Cerebrum	Higher cognitive functions, sensory processing, voluntary movement
Cerebellum	Coordination of movement, balance
Diencephalon	Thalamus (relay center), hypothalamus (homeostasis)
Brainstem	Autonomic functions, cranial nerve nuclei

Additional info: These study notes expand upon the practical outline by providing definitions, examples, and tables for key anatomical and physiological concepts relevant to the skeleton, muscles, and nervous system. All bolded terms in the original outline are included and explained for comprehensive exam preparation.