INI CET Anatomy Syllabus

What are the two principal cell types of nervous tissue and their roles?

Neurons, which generate and conduct electrical impulses, and neuroglia (glial cells), which support, nourish, insulate, and protect neurons.

Name the parts of a typical neuron.

Dendrites (receive signals), cell body/soma (contains nucleus), axon (conducts impulses away), and axon terminals (transmit signals at synapses).

What are the main functions of bone (osseous) tissue?

Support, protection of organs, movement (levers for muscles), mineral storage (calcium and phosphate), blood cell formation (hematopoiesis in red marrow), and energy/fat storage (yellow marrow).

How are bones classified by shape, with an example of each?

Long (femur, humerus), short (carpals, tarsals), flat (sternum, scapula, skull bones), irregular (vertebrae, hip bone), and sesamoid (patella).

What is the difference between compact and spongy (cancellous) bone?

Compact bone is dense, forms the outer shell, and is organized into osteons (Haversian systems). Spongy bone consists of a trabecular lattice with marrow-filled spaces and is found internally, e.g., at bone ends.

Identify the main gross regions of a typical long bone.

Diaphysis (shaft), epiphyses (ends), metaphysis (between diaphysis and epiphysis, containing the growth plate), epiphyseal (growth) plate/line, periosteum (outer covering), endosteum, and medullary (marrow) cavity.

Name the four types of bone cells and their functions.

Osteoblasts (form/deposit bone matrix), osteocytes (mature cells maintaining matrix, residing in lacunae), osteoclasts (resorb bone), and osteoprogenitor/osteogenic cells (stem cells).

What are the two types of bone ossification (development)?

Intramembranous ossification (bone forms directly within a fibrous membrane, e.g., flat bones of the skull and clavicle) and endochondral ossification (bone replaces a hyaline cartilage model, e.g., long bones).

What is the role of the epiphyseal plate, and what happens when growth ends?

The epiphyseal (growth) plate allows longitudinal bone growth via cartilage proliferation and ossification; when growth ceases it ossifies and becomes the epiphyseal line.

What is a joint (articulation)?

A joint is the site where two or more bones (or bone and cartilage) meet; it provides connection and may allow varying degrees of movement.

How are joints classified structurally and functionally?

Structurally: fibrous, cartilaginous, and synovial. Functionally: synarthrosis (immovable), amphiarthrosis (slightly movable), and diarthrosis (freely movable).

Give examples of fibrous and cartilaginous joints.

Fibrous: sutures of the skull (synarthrosis), syndesmoses (e.g., distal tibiofibular), gomphoses (teeth in sockets). Cartilaginous: synchondroses (epiphyseal plate, costal cartilage) and symphyses (pubic symphysis, intervertebral discs).

What are the defining structural features of a synovial joint?

A fluid-filled joint cavity, articular (hyaline) cartilage on bone ends, an articular capsule (fibrous outer layer plus synovial membrane), synovial fluid for lubrication, and reinforcing ligaments; many have bursae or menisci.

What is the function of synovial fluid?

It lubricates and reduces friction between articular cartilages, absorbs shock, and nourishes the avascular articular cartilage.

Name the six types of synovial joints with an example of each.

Plane/gliding (intercarpal), hinge (elbow), pivot (atlantoaxial), condyloid/ellipsoid (radiocarpal/wrist), saddle (carpometacarpal of thumb), and ball-and-socket (hip, shoulder).

Which synovial joint type allows the greatest range of motion, and which is uniaxial?

Ball-and-socket joints (multiaxial) allow the greatest range of motion; hinge and pivot joints are uniaxial (movement around one axis).

What are the three connective tissue layers organizing a skeletal muscle from outer to inner?

Epimysium (surrounds the whole muscle), perimysium (surrounds fascicles/bundles of fibers), and endomysium (surrounds individual muscle fibers).

Define the origin and insertion of a skeletal muscle.

The origin is the muscle's attachment to the more stationary (usually proximal) bone; the insertion is the attachment to the more movable (usually distal) bone that moves toward the origin on contraction.

What is meant by muscle architecture (fascicle arrangement)? Give examples.

It describes the orientation of fascicles relative to the tendon. Types include parallel (sartorius), fusiform (biceps brachii), pennate — unipennate, bipennate, multipennate (deltoid), convergent (pectoralis major), and circular/sphincter (orbicularis oris).

What is the functional/structural unit of a skeletal muscle fiber, and what defines its boundaries?

The sarcomere, the contractile unit, extends from one Z-line (Z-disc) to the next. It contains thick (myosin) and thin (actin) filaments and produces the striated banding pattern.

Identify the bands and lines of a sarcomere.

A-band (dark, full length of thick filaments), I-band (light, thin filaments only, bisected by the Z-line), H-zone (thick filaments only, center), M-line (center of H-zone), and Z-line/disc (boundary of sarcomere).

What are the two main divisions of the nervous system, and what comprises each?

Central nervous system (CNS): brain and spinal cord. Peripheral nervous system (PNS): cranial nerves, spinal nerves, ganglia, and sensory receptors.

What are the major regions of the brain?

Cerebrum (two hemispheres with lobes), diencephalon (thalamus, hypothalamus, epithalamus), brainstem (midbrain, pons, medulla oblongata), and cerebellum.

Name the four lobes of the cerebrum and a key function of each.

Frontal (voluntary motor control, planning, personality), parietal (somatosensory processing), temporal (hearing, memory), and occipital (vision).

How many ventricles does the brain have, and what are they?

Four: two lateral ventricles (in the cerebral hemispheres), the third ventricle (in the diencephalon), and the fourth ventricle (between brainstem and cerebellum).

Trace the circulation of cerebrospinal fluid (CSF) from production to absorption.

CSF is produced by the choroid plexus in the lateral ventricles → through the interventricular foramina (of Monro) to the third ventricle → cerebral aqueduct (of Sylvius) → fourth ventricle → exits via the foramina of Luschka and Magendie into the subarachnoid space → absorbed into venous blood by arachnoid granulations.

What are the functions of cerebrospinal fluid?

It cushions/protects the brain and spinal cord, provides buoyancy to reduce brain weight, removes metabolic waste, and helps maintain a stable chemical environment.

Describe key features of the spinal cord (extent and enlargements).

It extends from the foramen magnum to about the L1–L2 vertebral level, ending as the conus medullaris (continuing as the cauda equina). It has cervical and lumbar enlargements for the limbs, and its central gray matter is butterfly/H-shaped surrounded by white matter.

How are cranial and spinal nerves of the PNS numbered?

There are 12 pairs of cranial nerves (CN I–XII) and 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.

What is surface anatomy and why is it clinically important?

Surface anatomy is the study of external body landmarks that reveal underlying structures. Clinically it guides palpation, auscultation, locating injection/venipuncture sites, finding pulse points, and planning surgical incisions. Example: the jugular notch, sternal angle (of Louis) marking the T4/T5 level and 2nd costal cartilage, and McBurney's point for the appendix.

Outline the early stages of human embryonic development through gastrulation.

Fertilization → cleavage → morula → blastocyst (with inner cell mass) → implantation → bilaminar disc (epiblast + hypoblast) → gastrulation forming the trilaminar disc with three germ layers.

Name the three primary germ layers and the main tissues each gives rise to.

Ectoderm (epidermis, nervous system), mesoderm (muscle, bone, connective tissue, cardiovascular and urogenital systems), and endoderm (epithelial lining of the gut, respiratory tract, and associated glands like liver and pancreas).

What common medical imaging modalities are used in anatomy, and what is each best suited for?

X-ray/radiography (bones, dense structures), CT (cross-sectional, bone and acute bleeds, uses ionizing radiation), MRI (soft tissues, no ionizing radiation, uses magnetic fields), and ultrasound (real-time soft tissue/fluid, uses sound waves, no radiation). On standard CT/X-ray, dense bone appears white (radiopaque) and air appears black (radiolucent).