Anatomy and Physiology: Comprehensive Course Review

Comprehensive vocabulary flashcards covering both skeletal muscle excitation-contraction coupling and foundational anatomy and physiology concepts, including body organization, histology, organ systems, skeletal dynamics, and neural physiology.

Local (Graded) Potential (Muscle Cell)

The influx of $Na^+$ into the skeletal muscle cell from the extracellular fluid through ligand/chemically-gated $Na^+$ channels following acetylcholine (ACh) binding.

Action Potential (Sarcolemma)

A self-propagating, unstoppable wave of depolarization triggered when a local potential is strong enough to open voltage-gated $Na^+$ channels all over the sarcolemma and down the T-tubules.

Latent Period

The delay period during skeletal muscle stimulation prior to tension development, corresponding to an electrical threshold of about $-55\,mV$.

Troponin and Tropomyosin Interaction

The process wherein $Ca^{2+}$ released from the sarcoplasmic reticulum binds to troponin, causing it to change position, pivot, and pull tropomyosin off the active sites on actin filaments.

Sliding Filament Mechanism

The process by which exposed actin active sites bind to myosin heads, which pull or ratchet actin filaments toward the center of the sarcomere, shortening the muscle cell.

Acetylcholinesterase (AChE)

An enzyme floating in the synaptic cleft and on the sarcolemma that breaks down acetylcholine (ACh) immediately after its release, initiating muscle relaxation.

Muscle Cell Relaxation

The sequence in which AChE degrades ACh, ligand- and voltage-gated channels close, the sarcoplasmic reticulum actively pumps $Ca^{2+}$ back inside, and troponin-tropomyosin complexes recover the active sites on actin.

Repolarization of the Sarcolemma

The outward movement of $K^+$ through slow, sluggish voltage-gated $K^+$ ion channels, followed by the $Na^+/K^+$ pump moving ions back to re-establish the resting membrane potential (RMP).

Anatomy

The study of structure, often referred to as the 'naming of parts.'

Physiology

The study of function, or 'how does it work.'

Gross Anatomy

The study of structures of the human body that can be seen with the unaided eye.

Histology

The microscopic study of tissues.

Levels of Structural Organization

The hierarchy of human organization consisting of six levels: Chemical level, Cellular level, Tissue level, Organ level, Organ system level, and Organism level.

Computed Tomography (CT) Scan

A medical imaging technique that uses ionizing radiation to gather data, which is fed to a computer to produce a 3-D image.

Magnetic Resonance Imaging (MRI)

An imaging technique produced by placing the body within a magnetic field, where a computer compiles data from the scan to produce a 3-D image.

Positron Emission Tomography (PET)

An imaging test that uses radioactive material to diagnose a variety of diseases such as tumors, heart disease, and brain disorders.

Ultrasound

An imaging test that uses sound waves to create pictures of organs, tissues, and other structures inside the body.

Auscultation

The action of listening to sounds from the heart, lungs, or other organs, typically using a stethoscope, as part of medical diagnosis.

Palpation

A clinical examination method involving feeling body structures with the fingers or hands.

Homeostasis

The tendency of an organism to maintain a relatively constant internal environment within a normal range around a set point.

Autoregulation (Intrinsic Regulation)

A regulatory mechanism in which a cell, tissue, organ, or organ system adjusts its activities independently (e.g., heart rate intrinsic mechanisms or digestive functions).

Negative Feedback Mechanism

The most common feedback mechanism in the body, wherein the end result opposes the initial change to bring the variable back to normal.

Positive Feedback Mechanism

A rare feedback mechanism where the end result increases or amplifies the initial change, functioning rapidly with built-in brakes (e.g., blood clotting and labor pains).

Anatomical Position

A standard reference frame where the body is standing upright, feet shoulder-width apart, upper limbs at the sides of the trunk, with head and palms facing forward.

Body Cavities

Hollow spaces within the body that house internal organs, categorized into the cranial, vertebral (spinal), thoracic (containing pleural and mediastinum cavities), and abdominopelvic cavities.

Serous Membranes (Mesothelium)

Two-layered membranes with serous fluid between them (a visceral layer touching the organ and a parietal layer attaching to surroundings) that hold organs in place and reduce friction.

Cell Adhesion Molecules (CAMs)

Cell-surface glycoproteins and proteins that bind cells to each other or to the extracellular matrix (ECM).

Tight Junctions

Intercellular connections that seal adjacent cells together, making the space between them impermeable (found lining the digestive tract).

Gap Junctions

Protein channels between adjacent cells that allow small substances and ions to pass directly from one cell to another (found in cardiac muscle).

Desmosomes

Intercellular junctions that mechanically link cells together, increasing the tissue's resistance to mechanical stress (found in the epidermis of the skin).

Merocrine Secretion

A type of exocrine gland secretion in which secretory products are packaged into vesicles and released via exocytosis without loss of cellular cytoplasm.

Cutaneous Membrane

The skin, an organ composed of a superficial stratified squamous epithelium (epidermis) anchored to an underlying vascular connective tissue dermis.

Stratum Basale

The deepest single layer of cuboidal keratinocytes in the epidermis, attached to the basement membrane, displaying active mitosis and housing melanocytes.

Calcitriol

The active form of vitamin D synthesized in the kidney from cholecalciferol ($\text{Vitamin } D_3$), which promotes calcium and phosphate absorption from food in the gut.

Dermal Papillae

Projections of the papillary dermis into the epidermis that contain capillary loops and tactile corpuscles for light touch reception.

Eponychium

The distal edge of the proximal nail fold, commonly called the cuticle, consisting of stratum corneum covering the nail root.

Tension Lines (Cleavage Lines)

Patterns formed by gaps between collagen bundles in the reticular dermis; incisions parallel to them heal faster with less scarring.

Albinism

An inherited condition where melanocytes fail to manufacture tyrosinase, preventing melanin synthesis and increasing keratinocyte susceptibility to UV damage.

Periosteum

A double-layered membrane composed of dense irregular connective tissue, rich in blood vessels and nerves, anchored to bone by perforating fibers.

Hydroxyapatite

The primary inorganic mineral salt ($Ca_{10}(PO_4)_6(OH)_2$) constituting about $65\%$ of dry bone matrix weight, providing compressive strength.

Osteoclast

A large, multinucleated cell derived from white blood cell lineages that secretes acids and enzymes to dissolve and dismantle the bony matrix.

Epiphyseal Plate Zones

The distinct functional regions of growing bone, ordered as: zone of proliferation, zone of hypertrophy and maturation, zone of calcification, and zone of ossification.

Endochondral Ossification

The ossification process that replaces a hyaline cartilage model with bone tissue, forming primary ossification centers in the diaphysis and secondary centers in the epiphyses.

Calcitonin

A thyroid hormone ('bone builder') released during hypercalcemia that inhibits osteoclast activity, favoring bone formation over bone resorption.

Parathyroid Hormone (PTH)

A hormone from the parathyroid glands ('bone breaker') secreted during hypocalcemia that stimulates osteoclast activity to release calcium into the bloodstream.

Spinal Curvatures

The four natural curves of the adult vertebral column: concave cervical and lumbar curvatures, and convex thoracic and sacral curvatures.

Joint (Articulation)

Any site where two or more bones meet, categorized structurally as fibrous, cartilaginous, or synovial, and functionally as synarthroses, amphiarthroses, or diarthroses.

Tibial Collateral Ligament (MCL)

A stabilizing ligament on the medial side of the knee joint frequently torn alongside the anterior cruciate ligament (ACL) and medial meniscus in lateral impact knee injuries.

Gout

An inflammatory arthritis more prevalent in men caused by excess uric acid in the blood, leading to crystal deposition in joint spaces.

Epimysium

A sheath of dense connective tissue that encloses the entire skeletal muscle exterior.

Perimysium

A dense irregular connective tissue layer that groups individual skeletal muscle fibers into bundles called fascicles.

Endomysium

A delicate layer of reticular connective tissue fibers that surrounds each individual skeletal muscle fiber.

Class 3 Lever

The most common musculoskeletal lever in the human body, in which the effort (muscle force) is located between the fulcrum and the load, sacrificing force for range of motion and speed.

Skeletal Muscle Fiber

An elongated, cylindrical, multinucleated muscle cell with distinct transverse striations produced by repeating sarcomeric arrangements.

Length-Tension Relationship

The physiological principle showing that maximal contractile tension occurs at an optimal sarcomere resting length ($100\%$ to $120\%$), decreasing when overly shortened or stretched.

Muscle Adaptations to Training and Disuse

Structural adjustments including increased mitochondria and capillaries from endurance training, increased myofibrils and fiber diameter from resistance training, and myofibril loss from disuse.

Neuromuscular Junction (NMJ)

The specialized synapse between a motor neuron terminal and the motor end plate of a muscle fiber sarcolemma where acetylcholine transmits electrical excitation.

Neuroglia of the Central Nervous System

The four supportive glial cell classes of the brain and spinal cord: astrocytes (blood-brain barrier), oligodendrocytes (myelination), microglial cells (phagocytes), and ependymal cells (CSF production/circulation).

Synapse Types (Electrical vs. Chemical)

Electrical synapses transmit direct current instantaneously via gap junctions, whereas chemical synapses convert electrical signals into chemical neurotransmitters across a synaptic cleft.

Neurotransmitters

Signaling molecules classified chemically into acetylcholine, biogenic amines, amino acids, and neuropeptides that elicit EPSPs or IPSPs via ionotropic or metabotropic receptors.

Cerebrospinal Fluid (CSF) Circulation

The movement of fluid produced by ependymal cells of the choroid plexuses through the brain ventricles and subarachnoid space, reabsorbed into the superior sagittal sinus via arachnoid granulations.

Hypothalamic Nuclei

Specialized clusters of neuronal cell bodies within the anterior, middle, and posterior hypothalamus regulating body temperature, circadian rhythms, thirst, hunger, sleep, and the autonomic nervous system.

Spinal Cord Gross Anatomy

The cylindrical CNS structure terminating around the $L_1-L_2$ vertebrae as the conus medullaris, anchored by the filum terminale and giving rise to the cauda equina.

Sleep Stages

A cyclic progression consisting of non-REM stages (Stage I theta waves, Stage II slower theta, Stage III very slow theta, Stage IV delta waves) and REM sleep exhibiting beta-like brain waves.

Spinal Nerve Structure

A mixed nerve formed by the union of posterior (sensory) and anterior (motor) roots, organized into endoneurium (surrounding single axons), perineurium (fascicles), and epineurium (outer nerve).

Reflex Arc

The simplest functional neural circuit, consisting of a sensory receptor detecting a stimulus, an afferent division leading to CNS integration, and an efferent motor division driving an effector response.

Autonomic Nervous System Divisions

The dual efferent visceral motor systems comprising the thoracolumbar sympathetic division (short preganglionic, long postganglionic fibers) and the craniosacral parasympathetic division (long preganglionic, short postganglionic fibers).

Refraction Abnormalities (Hyperopia and Myopia)

Hyperopia (farsightedness) results from a shortened eyeball causing images to focus behind the retina (corrected with convex lenses); myopia (nearsightedness) results from an elongated eyeball focusing images in front of the retina (corrected with concave lenses).

Fundus of the Eye

The interior posterior surface of the eye displaying retinal blood vessels radiating from the optic disc (blind spot) toward the macula lutea and fovea centralis.

Ear Anatomy

The auditory and vestibular apparatus divided into the outer ear (auricle, external auditory canal), middle ear (tympanic membrane, auditory ossicles), and inner ear (semicircular canals, vestibule, cochlea).