Chat Part 1

What are the three anatomical planes?

Sagittal divides left/right; frontal (coronal) divides anterior/posterior; transverse divides superior/inferior.

What is the anatomical position?

Standing upright, feet forward, arms at sides, palms facing anteriorly, thumbs lateral.

What is the difference between proximal and distal?

Proximal is closer to the point of attachment; distal is farther away.

What is the difference between medial and lateral?

Medial is toward the midline; lateral is away from the midline.

What is the difference between superficial and deep?

Superficial is closer to the body surface; deep is farther from the surface.

What are the four major tissue types?

Epithelial, connective, muscle, and nervous tissue.

What epithelium lines alveoli and is specialized for diffusion?

Simple squamous epithelium.

What epithelium commonly lines the trachea?

Pseudostratified ciliated columnar epithelium with goblet cells.

What epithelium lines most of the urinary bladder?

Transitional epithelium (urothelium).

What are the major functions of epithelial tissue?

Protection, absorption, secretion, filtration, and sensation.

What are the three types of cartilage?

Hyaline, elastic, and fibrocartilage.

Where is fibrocartilage classically found?

Intervertebral discs, pubic symphysis, and menisci.

What is the primary cell of mature bone?

Osteocyte.

What cell builds bone?

Osteoblast.

What cell resorbs bone?

Osteoclast.

What is the functional unit of compact bone?

The osteon (Haversian system).

What is the main mineral component of bone?

Hydroxyapatite, primarily calcium phosphate.

What are the four chambers of the heart?

Right atrium, right ventricle, left atrium, left ventricle.

What valve lies between the right atrium and right ventricle?

Tricuspid valve.

What valve lies between the left atrium and left ventricle?

Mitral (bicuspid) valve.

Which vessel carries oxygenated blood from the lungs to the heart?

Pulmonary veins.

Which vessel carries deoxygenated blood from the heart to the lungs?

Pulmonary arteries.

What is the largest artery in the body?

Aorta.

What is the largest vein in the body?

Inferior vena cava.

What are the major components of the lymphatic system?

Lymph, lymphatic vessels, lymph nodes, spleen, thymus, and other lymphoid tissues.

What is the primary lymphoid organ where T cells mature?

Thymus.

What organ filters blood and removes old RBCs?

Spleen.

What is the main function of the diaphragm?

Primary muscle of inspiration.

What is the main muscle of quiet expiration?

Expiration is normally passive due to elastic recoil.

What is the functional unit of the kidney?

Nephron.

What are the three major regions of the brain?

Cerebrum, brainstem, and cerebellum.

What structures make up the brainstem?

Midbrain, pons, and medulla oblongata.

What are the meninges from superficial to deep?

Dura mater, arachnoid mater, pia mater.

Where is CSF found between the meninges?

Primarily in the subarachnoid space.

What are the major components of the peripheral nervous system?

Cranial nerves, spinal nerves, peripheral nerves, and ganglia.

What is the autonomic nervous system divided into?

Sympathetic and parasympathetic divisions, with the enteric system often considered a third component.

What cranial nerve is responsible for smell?

CN I, olfactory.

What cranial nerve is responsible for vision?

CN II, optic.

What cranial nerve controls most extraocular movements?

CN III, oculomotor, along with CN IV and CN VI for the other extraocular muscles.

How many cervical vertebrae are there?

7.

How many thoracic vertebrae are there?

12.

How many lumbar vertebrae are there?

5.

How many sacral vertebrae are fused?

5.

How many coccygeal vertebrae are usually present?

Usually 3–5, commonly 4.

What makes C1 unique?

Atlas; it has no vertebral body and no typical spinous process.

What makes C2 unique?

Axis; its dens (odontoid process) projects superiorly.

What movement occurs primarily at the atlanto-occipital joints?

Flexion and extension ('yes' motion).

What movement occurs primarily at the atlantoaxial joint?

Rotation ('no' motion).

What ligament holds the dens against the anterior arch of C1?

Transverse ligament of the atlas.

What are the main curves of the vertebral column?

Cervical and lumbar lordoses; thoracic and sacral kyphoses.

When do primary spinal curves develop?

During fetal development; thoracic and sacral curves are primary.

When do secondary spinal curves develop?

Cervical lordosis with head control; lumbar lordosis with standing/walking.

What is a typical feature of cervical vertebrae?

Transverse foramina.

What artery commonly travels through the cervical transverse foramina?

Vertebral artery, typically C6–C1.

What is a key feature of thoracic vertebrae?

Costal facets for articulation with ribs.

What is a key feature of lumbar vertebrae?

Large vertebral bodies and robust processes for weight bearing.

What is the zygapophyseal joint?

A synovial facet joint between articular processes of adjacent vertebrae.

What type of joint is an intervertebral disc symphysis?

Secondary cartilaginous joint (symphysis).

What are the two major parts of an intervertebral disc?

Annulus fibrosus and nucleus pulposus.

What is the nucleus pulposus derived from embryologically?

Notochord.

What is the annulus fibrosus composed primarily of?

Concentric layers of fibrocartilage and collagen fibers.

What is the orientation of lumbar facet joints best suited to?

Flexion/extension with relatively limited rotation.

What is the orientation of cervical facets?

Oblique, allowing substantial flexion, extension, lateral flexion, and rotation.

What is the main motion of thoracic facets?

They favor rotation while limiting flexion/extension compared with lumbar facets.

What are the costovertebral joints?

Synovial joints between rib heads and thoracic vertebral bodies/discs.

What are the costotransverse joints?

Synovial joints between rib tubercles and transverse processes of thoracic vertebrae.

What is the pump-handle motion of ribs?

Upper ribs elevate with increased anteroposterior thoracic diameter.

What is the bucket-handle motion of ribs?

Middle/lower ribs elevate with increased transverse thoracic diameter.

What is the primary respiratory rib?

The first rib is atypical; ribs 2–6 are commonly associated with pump-handle mechanics and 7–10 with bucket-handle mechanics.

What is the ligamentum flavum?

Elastic ligament connecting adjacent vertebral laminae.

What is the anterior longitudinal ligament's major role?

Limits excessive spinal extension.

What is the posterior longitudinal ligament's major role?

Runs inside the vertebral canal and helps limit spinal flexion.

What is the supraspinous ligament?

Ligament connecting the tips of spinous processes.

What is the ligamentum nuchae?

Continuation/expansion of the supraspinous ligament in the cervical region.

What is the spinal cord's adult termination level?

Approximately L1–L2 vertebral level in adults.

What is the cauda equina?

Bundle of lumbar, sacral, and coccygeal nerve roots below the conus medullaris.

What is the conus medullaris?

Tapered inferior end of the spinal cord.

What is the denticulate ligament?

Pial extension that helps anchor the spinal cord laterally to the dura.

What is the most common direction of cervical disc herniation?

Posterolateral, where it may affect an exiting/descending nerve root depending on level and anatomy.

What is the resting membrane potential of a typical neuron?

Approximately −70 mV.

What ion is most responsible for the resting membrane potential?

K+ permeability through leak channels, with the Na+/K+ ATPase maintaining gradients.

What happens during neuronal depolarization?

Voltage-gated Na+ channels open and Na+ enters the cell.

What causes repolarization of an action potential?

Na+ channels inactivate and voltage-gated K+ channels allow K+ efflux.

What is the absolute refractory period?

Period when another action potential cannot be generated regardless of stimulus strength.

What is saltatory conduction?

Action potential propagation by 'jumping' between nodes of Ranvier on myelinated axons.

What neurotransmitter is released at the neuromuscular junction?

Acetylcholine.

What receptor does ACh bind on skeletal muscle?

Nicotinic acetylcholine receptor.

What is the sliding filament mechanism?

Actin slides past myosin, shortening the sarcomere without shortening the filaments themselves.

What ion initiates skeletal muscle contraction?

Ca2+ released from the sarcoplasmic reticulum.

What protein binds calcium in skeletal muscle?

Troponin C.

What blocks actin's myosin-binding sites at rest?

Tropomyosin.

What is the Frank-Starling law?

Within physiological limits, increased ventricular filling increases stretch and produces a stronger contraction.

What is cardiac output?

Heart rate × stroke volume.

What is mean arterial pressure approximately?

DBP + 1/3 pulse pressure at normal resting heart rates.

What determines blood pressure most directly?

Cardiac output × systemic vascular resistance.

What is the main pacemaker of the heart?

Sinoatrial (SA) node.

What is the normal conduction sequence through the heart?

SA node → atria → AV node → bundle of His → bundle branches → Purkinje fibers.

What is the purpose of the AV nodal delay?

Allows time for ventricular filling after atrial contraction.

What does the P wave represent?

Atrial depolarization.

What does the QRS complex represent?

Ventricular depolarization.