Anatomy & Physiology Study Guide: Body Landmarks, Cell Structures, and Nervous System

Body Surface Landmarks and Anatomical Terminology

Body Surface Landmarks

Body surface landmarks are specific regions of the body used to describe locations and relationships in anatomy. Understanding these terms is essential for identifying anatomical structures and communicating their positions.

• Abdominal: Relating to the abdomen.

• Acromial: Shoulder region.

• Antebrachial: Forearm.

• Antecubital: Front of elbow.

• Axillary: Armpit.

• Brachial: Arm (upper arm).

• Buccal: Cheek area.

• Carpal: Wrist.

• Cephalic: Head.

• Cervical: Neck.

• Coxal: Hip.

• Crural: Leg (lower leg).

• Digital: Fingers or toes.

• Femoral: Thigh.

• Fibular: Side of leg.

• Frontal: Forehead.

• Hallux: Big toe.

• Inguinal: Groin.

• Manus: Hand.

• Mental: Chin.

• Nasal: Nose.

• Oral: Mouth.

• Orbital: Eye socket.

• Palmar: Palm of hand.

• Patellar: Front of knee.

• Pedal: Foot.

• Pelvic: Pelvis.

• Pollex: Thumb.

• Sternal: Breastbone.

• Tarsal: Ankle.

• Thoracic: Chest.

• Calcaneal: Heel.

• Gluteal: Buttocks.

• Lumbar: Lower back.

• Occipital: Back of head.

• Olecranal: Back of elbow.

• Otic: Ear.

• Perineal: Area between anus and external genitalia.

• Plantar: Sole of foot.

• Popliteal: Back of knee.

• Sacral: Area between hips.

• Scapular: Shoulder blade.

• Sural: Calf.

Abdominopelvic Regions

The abdominopelvic region is divided into nine areas for precise anatomical description.

Region	Location
Right hypochondriac	Upper right, beneath the ribs
Right lumbar	Middle right
Right iliac/inguinal	Lower right
Epigastric	Upper middle
Umbilical	Center, around the navel
Hypogastric	Lower middle
Left hypochondriac	Upper left, beneath the ribs
Left lumbar	Middle left
Left iliac/inguinal	Lower left

Directional Terms

Directional terms describe the relative positions of body parts.

• Superior: Above; toward the head.

• Inferior: Below; away from the head.

• Anterior (ventral): Toward the front.

• Posterior (dorsal): Toward the back.

• Medial: Toward the midline.

• Lateral: Away from the midline.

• Proximal: Closer to the point of attachment.

• Distal: Farther from the point of attachment.

• Superficial: Near the surface.

• Deep: Away from the surface.

Example: The heart is medial to the lungs and superior to the diaphragm.

Cellular Structures and Cell Division

Cell Structures

Cells are the basic units of life, containing specialized structures called organelles that perform distinct functions.

• Ribosomes: Sites of protein synthesis.

• Rough Endoplasmic Reticulum (Rough ER): Studded with ribosomes; synthesizes and processes proteins.

• Smooth Endoplasmic Reticulum (Smooth ER): Synthesizes lipids and detoxifies chemicals.

• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.

• Lysosomes: Contain digestive enzymes for breaking down waste.

• Peroxisomes: Break down fatty acids and detoxify harmful substances.

• Mitochondria: Produce ATP through cellular respiration.

• Centrioles: Organize microtubules during cell division.

• Microfilaments: Support cell shape and movement.

• Intermediate Filaments: Provide structural stability.

• Microtubules: Maintain cell shape and facilitate transport.

• Nucleus: Contains genetic material (DNA).

• Vesicles: Transport materials within the cell.

• Nucleolus: Produces ribosomes.

• Plasma Membrane: Controls entry and exit of substances.

• Nuclear Envelope: Surrounds the nucleus.

• Microvilli: Increase surface area for absorption.

• Cilia: Move substances across cell surfaces.

Cell Division: Mitosis

Mitosis is the process by which a cell divides to produce two identical daughter cells. It is essential for growth, repair, and maintenance.

• Interphase: Cell prepares for division; DNA replicates.

• Early Prophase: Chromatin condenses into chromosomes; spindle fibers begin to form.

• Late Prophase: Nuclear envelope breaks down; chromosomes attach to spindle fibers.

• Metaphase: Chromosomes align at the cell's equator.

• Anaphase: Sister chromatids separate and move to opposite poles.

• Telophase: Nuclear envelopes reform; chromosomes decondense.

• Cytokinesis: Cytoplasm divides, forming two cells.

Example: Skin cells undergo mitosis to replace damaged tissue.

Nervous Tissue and the Brain

Neuron Structure

Neurons are specialized cells that transmit electrical signals in the nervous system. Each part of the neuron has a specific function.

• Dendrite: Receives signals from other neurons.

• Cell body (soma): Contains nucleus, nucleolus, Nissl bodies (rough ER), and neurofibrils.

• Axon: Conducts impulses away from the cell body.

• Myelin sheath: Insulates axon, speeds up signal transmission.

• Node of Ranvier: Gaps in myelin sheath; facilitate rapid conduction.

• Telodendria/Axon Terminal: Transmit signals to other cells.

• Nucleus of Neuroglia: Support cells in nervous tissue.

Types of Neurons

Neurons are classified based on their structure and function.

Type	Structure	Function
Unipolar	One process	Sensory neurons
Bipolar	Two processes	Special senses (e.g., retina)
Multipolar	Many processes	Motor neurons, interneurons
Anaxonic	No clear axon	Integrative functions

Connective Tissue of Nerves

Nerves are surrounded by connective tissue layers that protect and organize them.

• Epineurium: Outermost layer; surrounds entire nerve.

• Perineurium: Surrounds bundles (fascicles) of axons.

• Endoneurium: Surrounds individual axons.

• Fascicle: Bundle of nerve fibers.

• Peripheral nerve: Nerve outside the central nervous system.

Brain Anatomy

The brain is divided into several regions, each with distinct functions.

• Lobes:

  • Frontal lobe: Reasoning, planning, movement.

  • Parietal lobe: Sensory perception.

  • Temporal lobe: Hearing, memory.

  • Occipital lobe: Vision.

• Corpus callosum: Connects left and right hemispheres.

• Fornix: Part of limbic system; involved in memory.

• Cerebellum: Coordinates movement; contains gray matter and arbor vitae (white matter).

• Diencephalon:

  • Pineal gland: Regulates sleep cycles.

  • Thalamus: Relay station for sensory information.

  • Hypothalamus: Controls homeostasis.

  • Infundibulum: Connects hypothalamus to pituitary gland.

  • Pituitary gland: Secretes hormones.

  • Mammillary bodies: Involved in memory.

• Brainstem:

  • Midbrain: Visual and auditory processing.

  • Pons: Relays information; regulates breathing.

  • Medulla oblongata: Controls vital functions (heart rate, breathing).

Cranial Nerves

There are twelve pairs of cranial nerves, each with specific functions. Students should know their names, functions, and locations.

Number	Name	Function
I	Olfactory	Smell
II	Optic	Vision
III	Oculomotor	Eye movement
IV	Trochlear	Eye movement
V	Trigeminal	Sensory to face, motor to jaw
VI	Abducens	Eye movement
VII	Facial	Facial expression, taste
VIII	Vestibulocochlear	Hearing, balance
IX	Glossopharyngeal	Taste, swallowing
X	Vagus	Parasympathetic control
XI	Accessory	Neck muscles
XII	Hypoglossal	Tongue movement

Example: The facial nerve (VII) controls muscles of facial expression and conveys taste sensations from the anterior tongue.

Additional info: Academic context was added to expand brief lists into full explanations and to clarify anatomical relationships and functions.