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MK Anatomy
Anatomy Fundamentals (PREMATRIC)
Question | Answer |
---|---|
Anatomical Planes of Reference | 1. Coronal (Frontal) Plane 2. Axial (Transverse) Plane 3. Sagittal Plane |
Coronal (Frontal) Plane | Divides body into anterior (or ventral) and posterior (or dorsal) parts. |
Axial (Transverse) Plane | Divides body into superior (or cephalic or cephalad) and inferior (or caudal or caudad) portions |
Sagittal Plane | Divides body into right and left parts (midsagittal/median line). -medial is the middle of the body and lateral is the sides of the body. -parasagittal is sometimes used to describe a plane parallel to the midline. |
Proximal | closer to the torso or closer to the beginning of a system |
Distal | Farther away from the torso or farther away from the beginning of a system |
Superficial | closer to the surface of the body or body part or organ; also closer to the start. |
Deep | farther from the surface of the body part of organ; farther from the start of a dissection |
Intermediate | somewhere between superficial and deep |
Fascia | visibly organized, sheetlike connective tissue of varying thickness and composition. -2 types: superficial & deep |
Superficial Fascia | the building blocks of skin; contains varying amounts of adipose tissue. |
Deep Fascia | surrounds and supports structure; forms fascial compartments and fascial planes. |
Clinical Note: Compartment syndrome | high compartment pressure that causes ischemia (restriction in blood supply). |
Axial Skeleton | 1. skull 2. spinal column 3. ribs and sternum 4. hyoid bone |
Appendicular Skeleton | 1. Pectoral girdle (scapula and clavicle) 2. pelvic girdle (hip bones) 3. free limbs (arms & legs) |
Cardiovascular System | two types of circulation: 1. Pulmonary circulation 2. Systemic circulation |
Pulmonary Circulation | blood that undergoes exchange passes thru one set of capillaries before returning to the heart. |
Systemic Circulation | Before or after exchange in a capillary bed, the blood may carry special substances or may need to be processed further before returning to the heart. |
Arteries | carry blood away from the heart (to the organs) |
Veins | Carry blood towards the heart |
Pulmonary arteries & Systemic veins carry... | deoxygenated blood |
Pulmonary veins & Systemic arteries carry... | oxygenated blood |
Elastic arteries (conducting arteries) | - the aorta and pulmonary artery permit smooth, pulsatile flow. -the elastic arteries branch off into muscular arteries. |
Muscular arteries (distributing arteries) | -maintain tonus & regulate flow of blood to large tissue masses. -They branch off into arterioles. |
Arterioles (resistance vessels) | -control the microcirculation to the exchange vessels, the capillaries and postcapillary venules. |
Two Variations in Systemic Circulation | 1. Nephron circulation 2. Portal system |
Nephron circulation | in the nephron, an arterial capillary bed (glomerulus) is interposed between a proximal afferent and distal efferent arteriole. the eff arteriole branches to form a 2nd true capillary bed (peritubular capillaries) |
Portal system | consists of true capillary beds (having arterial and venous sides) connected to beds of venous capillaries called sinusoids via portal vessels. |
Venous System | blood is conveyed BACK TO THE HEART via capacitance or reservoir vessels as either deoxy (venae cavae to the 'right heart') or oxy (pulm veins to 'left heart') blood. |
A feature of veins, but not arteries | the prescence of valves to assist return of blood to the heart. the valves are formed by one to three opposing semilunar leaflets & appear as dilation along veins of the neck & limbs. |
Deep veins | -generally accompany homonymous (same name) arteries, but superficial veins do not. -blood in superficial veins must eventually flow to deep veins in order to return to the heart. -deep veins of limbs are partially tethered to deep fascia btw muscle |
Musculovenous Pump | Rhythmical contraction of limb muscles. The contraction 'milks' the valve-oriented blood towards the heart. |
Varicose Veins | swollen, twisted, and sometimes painful veins that have filled with an abnormal collection of blood. caused by valvular incompetence which can occur by inflammatory destruction or deep fascial degeneration, causing them to gap. |
Thrombophlebitis | inflammation of a vein in response to thrombosis (clot). Left untreated, large thrombi may dislodge, travel to the right heart and form a pulmonary embolism. |
Pulmonary embolism | a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream, usually due venous thromboembolism. |
Venous Thromboembolism | a blood clot that forms within a vein. -deep venous thromboses (DVTs) form in the deep veins of the legs or in the pelvic veins . Since veins return to the heart, if a piece of clot breaks off, it can be transported into the lungs. |
Deep veins that lack valves... | are found in the head, thorax & abdomin, and pelvis. infectious agents and cancer can travel along these veins freely (hematogenous spread or metastasis) |
Homans' sign | passive dorsiflexion of the foot. (a test for DVT's which is falling out of favor due to emoblic risks.) |
Superficial vs. Large Veins (in regard to air embolism) | superficial veins will collapse when injured, however, large veins (like the internal jugular) will remain patent after injury b/c they are tethered to deep fascia. this can lead to fatal 'sucking' air embolism. |
Vascular Patterns (Homologous Connections) | To ensure REDUNDANCY of BLOOD SUPPLY and drainage to tissue masses, vessel engage in homologous connections called anastomoses. |
Anastomosis | the joining of similar blood vessels such that the net flow in some point of the anastomosis is zero. - 3 types: End-to-end, Transversal, and Convergence. |
End-to-end anastomosis | two blood vessels from different anatomical sources from a blunt union |
transversal anastomosis | a connecting vessel joins two vessels |
convergence anastomosis | two vessels converge to form a single vessel |
Accompanying veins (venae comitantes) | veins that course w/ and surround medium-sized arteries and are bound in the same vascular sheath. As the artery pulses, the valve-oriented blood in the Acc Veins is squeezed toward the heart. |
Angiosome | all the tissue supplied by an artery and its accompanying veins. |
Functional end-arteries | when an anastomosis is inadequate if sudden blockage occurs. (some anastomosis are insufficient to prevent ischemia w/ blockage of one artery. ex: coronary arteries) |
anatomical end-arteries | arteries that do not engage in anastomosis. (if they are blocked, the supplied territory becomes ischemic and dies.) |
Lymphatic Vascular System | made up of A. Primary lymphoid organs B. Secondary lymphoid organs & tissues |
Primary Lymphoid Organs | Production of lymphocytes -thymus gland -red bone marrow |
Secondary lymphoid organs & tissues | -spleen -mucosa-associated lymphoid tissues (MALT) -lymphatic vessels |
Mucosa-associated lymphoid tissues (MALT) - | consists of lymph nodes: small organs of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. |
Lymphatic Vessels | -lymphatic capillaries -afferent lymphatic vessels (to the lymph node) -efferent lymphatic vessels (leave a lymph node) -lymphatic trunks -lymphatic ducts |
Lymphatic Ducts | 1. right lymphovenous portal (right lymphatic ducts): drains lower half of body, left side of head and left extremity. 2. left lymphovenous portal (thoracic duct): drains above the diaphragm on the right, straight up thru the head and the right extremity |
Lymphatic Capillaries | drains interstitial fluid (10%) & lymph from around cell ready to be filtered and returned to the venous circulation. they are prevented from collapsing by being tethered to surrounding connective tissue which exerts traction around their openings. |
Interstitial Fluid | contains macromolecules, cell debris and microorganisms and is removed by lymphatic capillaries. |
lymphedema | localized fluid retention and tissue swelling (edema) caused by a compromised lymphatic system (lymphatic capillaries) |
Movement of lymph into lymphatic vessels is assisted by numerous valves and is the result of: | 1. transient rise in interstitial fluid pressure. 2. transient negative pressure of lumina from the intrinsic pumping of larger lymphatic vessel. 3. external compression by other tissues. 4. other forces (eg. gravity & intrathoracic pressure) |
Location of lymphatic capillaries | 1. only in tissues with a blood supply (absent in non-vascular tissues) 2. BUT not always found in tissues WITH a blood supply (not found in the thymus, eye, CNS, PNS, bone marrow) |
Lymphovenous Portals | enter the venous system at the right and left venous angles (junction of the right and left subclavian and internal jugular veins) 1. Right 2. Left |
Right Lymphovenous Portal | (right lymphatic duct): accepts the right subclavian, jugular & bronchomediastinal trunks. -Drainage territory is the right half of the body above the diaphragm.* |
Left Lymphovenous Portal | (Thoracic duct): commences near the diaphragm at the aortic hiatus, accept the R & L lumbar trunks & 2-3 intestinal trunks. -Drainage territory is the rest of the body (minus the right half above the diaphragm).* |
Abnormal Lymph Nodes | Lymphadenopathy |
Lymphogenous metastatis of cancer | lymphatic pathways and lymph nodes serves as a means to disseminate cancer cells. cancerous nodes tend to be hard, craggy, fixed and non-tender. |
Sentinel node | node with highest probability to be first destination that cancer cells from a tumor will drain into. |
Signal node | a palpable, cancerous node that 'signals' the prescence of a primary carcinoma deep within the body. |
Lymphadenitis | inflammation of a lymph node due to infection. node tends to be tender, warm, enlarged, soft and movable. |
Organization of Nervous System | Comprised of two parts: 1. Central Nervous System (CNS) 2. Peripheral Nervous System (PNS) |
Central Nervous System (CNS) | 1. made of neuronal cell bodies, nerve fibers & connective tissues of brain & spinal cord 2. communicates w/ other functional units of body via PNS 3. collection of neuronal cell bodies w/in CNS (aka. nuclei) 4. Collection of axon w/in CNS (aka. tracts |
Peripheral Nervous System (PNS) | 1. comprised of neuronal cell bodies, nerve fibers & connective tissues OUTSIDE CNS 2. connects & conveys info btw peripheral structures & CNS 3. Collection of neuronal cell bodies outside CNS (aka Ganglion) 4. Collection of axons outside CNS (aka nerv |
Organization of Matter in Spinal Cord | Made up of White matter & Gray matter. -White matter is the outer region. -Gray matter is the inner region. |
Spinal Nerves | -31 pairs of spinal nerves from spinal cord -the volume of spinal cord contributing to a spinal nerve is a SPINAL CORD SEGMENT -dorsal and ventral rootlets of a segment fuse to form respective DORSAL and VENTRAL ROOTS, which merge to form a spinal nerve |
Dorsal & Ventral Roots | -merge to form a spinal nerve which is mixed: has both autonomic sensory (afferent) and motor (efferent) fibers, as well as sympathetic nerves. -Ventral root carries only motor fibers & Dorsal root only carries sensory fibers (Bell-Magendie Law) |
Neuron | anatomical unit of the nervous system consisting of a cell body, dendrites, & an axon. (classified as being multipolar, bipolar and unipolar.) |
2 types of Neurons | 1. Motor (efferent) 2. Sensory (afferent) |
Motor Neurons (efferent) | 1. multipolar & carries info AWAY from CNS 2. Cell bodies of somatic motor neurons located in nuclei within ventral horn of spinal cord 3. stimulate contraction of skeletal muscle (motor unit: single motor neuron & all the muscle cells it innervates) |
Sensory Neurons (afferent) | 1. unipolar & carries info TOWARDS CNS 2. cell bodies are clustered in ganglia located outside the CNS. The central process (axon) projects into the dorsal horn of spinal cord. 3. somatic (general) sensory neurons convey sensation from somatic structur |
types of Nerve Fibers | 1. somatic motor 2. somatic sensory 3. autonomic motor 4. autonomic sensory |
Branches of spinal nerves | -branches of spinal nerves are mixed fibers. -At the start, a spinal nerve divides into a dorsal ramus and a larger ventral ramus. The dorsal and ventral rami have somewhat specific regions of innervation. |
Territories of Innervation | 1. Dorsal Rami: Zygapophyseal joints, Intrinsic back muscles, skin of 2/3rds of back. 2. Ventral Rami: Everything else (form nerve plexuses - a network of intersecting nerves) |
how many & location of Spinal Nerves | -31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1* coccygeal (4 fused bones). -almost all these nerves occupy intervertebral (neural) foramen btw 2 vertebrae. |
How Spinal nerves are named | -SN C1 is btw skull and C1 vert. -SN C1-C7 are named for caudal vert of the neural foramen (vert below it). -SN C8 is located in the neural foramen btw C8 & T1 verts. (vert above it) -SN T1-Co1 are named for cephalad vert of the neural foramen? |
Dermatome | The region of skin innervated with a high contribution of single spinal nerve. |
Myotome | The mass of muscle innervated with a high component of a single spinal nerve. |