Key Takeaways
- Anatomy and physiology combined account for approximately 22 items (~36%) of the NEX Science section — nearly doubled from the old PAX
- Levels of organization: atoms → molecules → organelles → cells → tissues → organs → organ systems → organism
- Four tissue types: epithelial (covering/lining), connective (support/binding), muscle (movement), nervous (communication)
- Anatomical position: body facing forward, arms at sides, palms facing forward — all directions reference this position
- Body planes: sagittal (left/right), frontal/coronal (front/back), transverse (top/bottom)
- The integumentary system (skin) has three layers: epidermis, dermis, and hypodermis (subcutaneous)
- Skin functions include protection, temperature regulation, sensation, vitamin D synthesis, and excretion
- The skeletal system has 206 bones in adults, providing support, protection, movement, blood cell production, and mineral storage
Body Organization, Integumentary & Skeletal Systems
Anatomy and Physiology (combined) make up approximately 22 items (~36%) of the NEX Science section — this is nearly double the coverage on the old PAX exam. Understanding body systems is critical for nursing school readiness.
Levels of Body Organization
| Level | Description | Example |
|---|---|---|
| Chemical (Atoms) | Smallest unit of matter | Carbon, oxygen, hydrogen |
| Molecular | Atoms bonded together | Water (H₂O), glucose, DNA |
| Organelle | Structures within cells | Mitochondria, nucleus, ribosomes |
| Cellular | Basic unit of life | Red blood cell, neuron, epithelial cell |
| Tissue | Group of similar cells with a shared function | Epithelial tissue, muscle tissue |
| Organ | Two or more tissues working together | Heart, lungs, liver, kidneys |
| Organ System | Group of organs working together | Cardiovascular, respiratory, digestive |
| Organism | All organ systems functioning together | A human being |
The Four Tissue Types
| Tissue Type | Function | Locations | Examples |
|---|---|---|---|
| Epithelial | Covers surfaces, lines cavities, forms glands | Skin, organ linings, glands | Squamous, cuboidal, columnar |
| Connective | Supports, binds, protects | Throughout body | Bone, cartilage, blood, fat, tendons |
| Muscle | Produces movement | Attached to bones, heart, organ walls | Skeletal, cardiac, smooth |
| Nervous | Transmits electrical signals | Brain, spinal cord, nerves | Neurons, glial cells |
Three types of muscle tissue:
| Type | Control | Location | Characteristics |
|---|---|---|---|
| Skeletal | Voluntary | Attached to bones | Striated, multinucleated |
| Cardiac | Involuntary | Heart only | Striated, intercalated discs |
| Smooth | Involuntary | Organ walls (stomach, blood vessels, etc.) | Non-striated |
Anatomical Terminology
Body Planes
| Plane | Divides Body Into | Example |
|---|---|---|
| Sagittal (median) | Left and right halves | Cutting down the midline |
| Frontal (coronal) | Front (anterior) and back (posterior) | Cutting from ear to ear |
| Transverse (horizontal) | Top (superior) and bottom (inferior) | Cutting at the waist |
Directional Terms
| Term | Meaning | Opposite | Example |
|---|---|---|---|
| Superior | Above, toward head | Inferior | The heart is superior to the stomach |
| Inferior | Below, toward feet | Superior | The bladder is inferior to the kidneys |
| Anterior (ventral) | Front of the body | Posterior | The sternum is anterior to the spine |
| Posterior (dorsal) | Back of the body | Anterior | The kidneys are posterior to the stomach |
| Medial | Toward the midline | Lateral | The nose is medial to the eyes |
| Lateral | Away from the midline | Medial | The ears are lateral to the eyes |
| Proximal | Closer to the trunk/origin | Distal | The elbow is proximal to the wrist |
| Distal | Farther from the trunk/origin | Proximal | The fingers are distal to the wrist |
| Superficial | Near the surface | Deep | The skin is superficial to muscle |
| Deep | Away from the surface | Superficial | Bones are deep to muscle |
The Integumentary System (Skin)
The skin is the body's largest organ, with three main layers:
| Layer | Description | Key Structures |
|---|---|---|
| Epidermis | Outermost layer; no blood vessels | Keratinocytes, melanocytes |
| Dermis | Middle layer; contains blood vessels and nerves | Hair follicles, sweat glands, sebaceous glands, nerve endings |
| Hypodermis (subcutaneous) | Deepest layer; fat and connective tissue | Adipose tissue, blood vessels |
Functions of the skin:
- Protection from pathogens, UV radiation, physical trauma
- Temperature regulation via sweating and blood vessel dilation/constriction
- Sensation through nerve receptors (touch, pressure, pain, temperature)
- Vitamin D synthesis when exposed to sunlight
- Excretion of small amounts of waste through sweat
The Skeletal System
The adult human skeleton has 206 bones divided into two divisions:
| Division | Description | Bones Included |
|---|---|---|
| Axial skeleton (80 bones) | Central axis of the body | Skull, vertebral column, rib cage, sternum |
| Appendicular skeleton (126 bones) | Limbs and their attachments | Arms, legs, pectoral girdle, pelvic girdle |
Functions of the skeletal system:
- Support — provides structural framework
- Protection — skull protects brain, ribs protect heart/lungs
- Movement — serves as attachment points for muscles
- Blood cell production — red marrow produces blood cells (hematopoiesis)
- Mineral storage — stores calcium and phosphorus
Types of joints:
| Joint Type | Movement | Example |
|---|---|---|
| Fibrous (immovable) | None | Skull sutures |
| Cartilaginous (slightly movable) | Limited | Vertebral discs, pubic symphysis |
| Synovial (freely movable) | Full range | Knee, shoulder, hip, elbow |
What are the four basic tissue types in the human body?
Which body plane divides the body into anterior (front) and posterior (back) portions?
Which layer of the skin contains blood vessels, hair follicles, and sweat glands?
The adult human skeleton contains _____ bones.
Type your answer below
Match each anatomical directional term to its correct meaning.
Match each item on the left with the correct item on the right
Which type of muscle tissue is found ONLY in the heart?
The process of blood cell production in red bone marrow is called:
Which of the following are functions of the skeletal system? (Select all that apply)
Select all that apply
The correct hierarchy of body organization from simplest to most complex is:
Epithelial tissue is found in all of the following EXCEPT:
The transverse plane divides the body into which two portions?