Body Organization and Terminology

Anatomical Directions

Understanding anatomical directions is essential for describing locations and relationships of body structures.

• Superior: Toward the head or upper part of a structure.

• Inferior: Away from the head or toward the lower part of a structure.

• Anterior (Ventral): Toward the front of the body.

• Posterior (Dorsal): Toward the back of the body.

• Medial: Toward the midline of the body.

• Proximal: Closer to the origin of the body part or point of attachment.

• Distal: Farther from the origin of a body part or point of attachment.

Planes of the Body

Body planes are imaginary lines used to divide the body into sections for anatomical study.

• Sagittal Section: Divides the body into right and left parts.

• Transverse (Horizontal) Section: Divides the body into superior and inferior parts.

• Frontal (Coronal) Section: Divides the body into anterior and posterior parts.

Body Cavities and Membranes

Body cavities house organs and are lined by membranes that protect and separate structures.

• Cranial Cavity: Contains the brain.

• Thoracic Cavity: Contains lungs and heart; includes pleural and pericardial cavities.

• Abdominopelvic Cavity: Contains digestive, urinary, and reproductive organs.

• Membranes: Parietal and visceral layers (e.g., parietal pleura, visceral pleura).

Quadrants of the Abdomen

The abdomen is divided into four quadrants for clinical reference.

• Right and left upper quadrants

• Right and left lower quadrants

Tissues

Microscope Slides

Tissues are groups of cells with similar structure and function.

• Epithelial Tissue: Covers surfaces and lines cavities.

• Connective Tissue: Supports, binds, and protects organs.

• Muscle Tissue: Responsible for movement.

• Nervous Tissue: Conducts electrical impulses.

Skin Model

The skin consists of multiple layers and specialized structures.

• Epidermis: Outermost layer; includes stratum corneum, stratum basale.

• Dermis: Contains papillary and reticular layers, sweat glands, hair follicles, and sensory receptors.

• Hypodermis (Subcutaneous Layer): Contains adipose tissue.

Skeletal System

Bone Structure

Bones are classified by their structure and function.

• Compact Bone: Dense outer layer.

• Spongy Bone: Porous inner layer.

• Osteon: Structural unit of compact bone.

• Canaliculi: Small channels for nutrient exchange.

Axial Skeleton

The axial skeleton includes bones of the skull, vertebral column, and thoracic cage.

• Skull: Cranial and facial bones.

• Vertebral Column: Cervical, thoracic, lumbar vertebrae, sacrum, coccyx.

• Thoracic Cage: Sternum, ribs, costal cartilages.

Appendicular Skeleton

The appendicular skeleton consists of the limbs and girdles.

• Pectoral Girdle: Clavicle, scapula.

• Upper Limb: Humerus, radius, ulna, carpals, metacarpals, phalanges.

• Pelvic Girdle: Ilium, ischium, pubis.

• Lower Limb: Femur, tibia, fibula, tarsals, metatarsals, phalanges.

Joints and Muscle Tissue

Joints

Joints are classified by their structure and movement.

• Fibrous Joints (Synarthroses): Immovable; e.g., sutures of the skull.

• Cartilaginous Joints (Amphiarthroses): Slightly movable; e.g., intervertebral discs.

• Synovial Joints (Diarthroses): Freely movable; e.g., knee, elbow, shoulder.

Muscle Tissue

Muscle tissue is specialized for contraction and movement.

• Skeletal Muscle: Striated, voluntary.

• Cardiac Muscle: Striated, involuntary, intercalated discs.

• Smooth Muscle: Non-striated, involuntary.

Muscles

Muscles of the Head

Muscles in the head control facial expressions and movements.

• Frontalis, Occipitalis, Orbicularis oculi, Zygomaticus, Orbicularis oris, Masseter, Temporalis, Sternocleidomastoid

Muscles of the Chest and Back

• Trapezius, Latissimus dorsi, Serratus anterior, Pectoralis major, Deltoid, Teres major, Rotator cuff muscles (supraspinatus, infraspinatus, subscapularis)

Muscles of the Arm

• Deltoid, Triceps brachii, Biceps brachii, Brachialis, Brachioradialis

Muscles of the Abdomen and Hip

• External oblique, Rectus abdominis, Linea alba, Tendinous intersections

Muscles of the Leg

• Quadriceps femoris group (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius), Gluteus maximus, Gluteus medius, Hamstring group (biceps femoris, semitendinosus, semimembranosus), Gastrocnemius, Soleus, Achilles tendon

Fundamentals of the Nervous System

Nerve Cells

Neurons are specialized cells for transmitting electrical signals.

• Cell body (soma), nucleus, dendrites, axon, myelin sheath, Schwann cell, node of Ranvier

Central and Peripheral Nervous Systems

• Spinal cord: White matter, gray matter, dorsal/ventral roots, meninges (dura mater, arachnoid, pia mater)

• Human nervous system: Cranial nerves, spinal nerves, plexuses (cervical, brachial, lumbar, sacral)

• Autonomic nervous system: Sympathetic (yellow), parasympathetic (white)

Brain Structures

• Ventricles: Lateral, third, fourth ventricles; cerebral aqueduct

• Cerebrum: Hemispheres, corpus callosum, gyri, sulci, lobes (frontal, parietal, temporal, occipital)

• Diencephalon: Thalamus, hypothalamus

• Brainstem: Midbrain, pons, medulla oblongata

• Cerebellum: Arbor vitae, cerebellar cortex

• Other structures: Pineal body, olfactory bulbs, optic chiasma, pituitary gland

Senses

Skin Sensory Structures

• Meissner's corpuscle: Touch receptor

• Pacinian corpuscle: Pressure receptor

Tongue and Taste

• Papillae: Contain taste buds

• Taste buds: Sensory cells for taste

Ear Structures

• External ear: Auricle, external acoustic meatus, tympanic membrane

• Middle ear: Auditory ossicles (malleus, incus, stapes), auditory tube

• Inner ear: Bony and membranous labyrinth, cochlea, vestibule, semicircular canals

Eye Structures

• Fibrous tunic: Cornea, sclera

• Vascular tunic: Iris, ciliary body, choroid

• Nervous tunic: Retina, optic disc, fovea centralis

Sample Table: Types of Joints

Key Formulas and Equations

• Surface Area of a Sphere (e.g., for cell size): $A = 4\pi r^2$

• Volume of a Sphere: $V = \frac{4}{3}\pi r^3$

Additional info:

• Some anatomical terms and structures were expanded for clarity and completeness.

• Tables and formulas were added to provide academic context and support exam preparation.