ana

[CNS — CENTRAL NERVOUS SYSTEM] Explain: CNS = brain + spinal cord

CNS = brain + spinal cord; it is the processing/integration center. PNS connects the CNS to receptors, muscles, and glands.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Afferent = sensory information IN to CNS

Afferent = sensory information IN to CNS. Efferent = motor commands OUT from CNS.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Meninges

Meninges: dura mater → arachnoid mater → pia mater. From superficial to deep around the brain: scalp → skull → potential cranial epidural space → dura → potential subdural space → arachnoid → CSF-filled subarachnoid space → pia → brain.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: SCALP

SCALP: Skin → dense Connective tissue → Aponeurosis → Loose connective tissue → Pericranium.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: CSF route

CSF route: choroid plexus → lateral ventricles → interventricular foramina (Monro) → third ventricle → cerebral aqueduct → fourth ventricle → median/lateral apertures → subarachnoid space → arachnoid granulations → dural venous sinuses.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Choroid plexus PRODUCES CSF

Choroid plexus PRODUCES CSF; arachnoid granulations REABSORB CSF into dural venous sinuses.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Four brain regions

Four brain regions: cerebrum, diencephalon, brainstem, cerebellum. Cerebrum lobes: frontal—motor/judgment; parietal—somatic sensation; temporal—hearing/memory/language comprehension; occipital—vision; insula—visceral sensation/integration.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Central sulcus separates precentral gyrus (primary motor cortex, frontal) from…

Central sulcus separates precentral gyrus (primary motor cortex, frontal) from postcentral gyrus (primary somatosensory cortex, parietal). Sulcus = groove; gyrus = ridge.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Homunculus

Homunculus: face lateral, hand/arm intermediate, leg/foot medial. Gray matter = cell bodies; white matter = mostly myelinated axons. Brain: gray outside/white inside; spinal cord: gray inside/white outside.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Diencephalon

Diencephalon: thalamus—sensory relay; hypothalamus—homeostasis/pituitary control; pineal—melatonin. Brainstem: midbrain → pons → medulla; medulla contains vital cardiovascular/respiratory centers. Cerebellum: balance/coordination; arbor vitae = internal branching white matter.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Broca (frontal) = speech production

Broca (frontal) = speech production; Wernicke (temporal) = language comprehension; arcuate fasciculus connects them. Spinal cord: dorsal horn sensory, ventral horn motor; dorsal root/DRG sensory; ventral root motor.

[CNS — CENTRAL NERVOUS SYSTEM] Explain: Three major tracts

Three major tracts: dorsal column—fine touch/vibration; spinothalamic—pain/temperature; corticospinal—descending voluntary motor. Adult cord ends around L1–L2: conus medullaris; cauda equina = descending roots; filum terminale = anchoring strand.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: PNS sensory/afferent carries information to CNS

PNS sensory/afferent carries information to CNS; motor/efferent carries commands to effectors. Somatic = voluntary skeletal muscle; autonomic = mostly involuntary control.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Autonomic

Autonomic: sympathetic = fight or flight; parasympathetic = rest and digest.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: 31 pairs spinal nerves

31 pairs spinal nerves: 8C, 12T, 5L, 5S, 1Co. Dorsal sensory root + ventral motor root → mixed spinal nerve → dorsal ramus (deep back) + ventral ramus (trunk/limbs).

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Plexuses

Plexuses: cervical C1–C4; phrenic nerve C3–C5 to diaphragm. Brachial C5–T1: Roots → Trunks → Divisions → Cords → Branches. Lumbar L1–L4; sacral L4–S4.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Femoral nerve—knee extension

Femoral nerve—knee extension; obturator—thigh adduction; sciatic → tibial + common fibular. Dermatome = skin sensory area; myotome = muscle group associated with a spinal root.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Axillary—deltoid/teres minor

Axillary—deltoid/teres minor; musculocutaneous—anterior arm flexors; radial—extensors/wrist drop; median—forearm flexors/thenar/carpal tunnel; ulnar—many intrinsic hand muscles.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Cranial nerves

Cranial nerves: I Olfactory smell; II Optic vision; III Oculomotor most eye movement/pupil constriction; IV Trochlear superior oblique; V Trigeminal face sensation/chewing; VI Abducens lateral rectus.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: VII Facial—facial expression/anterior 2/3 taste/tears-saliva

VII Facial—facial expression/anterior 2/3 taste/tears-saliva; VIII Vestibulocochlear—hearing/balance; IX Glossopharyngeal—posterior 1/3 taste/parotid/swallowing; X Vagus—thoracoabdominal parasympathetic/pharynx-larynx; XI Accessory—SCM/trapezius; XII Hypoglossal—tongue motor.

[PNS — PERIPHERAL NERVOUS SYSTEM] Explain: Sympathetic

Sympathetic: T1–L2, short preganglionic/long postganglionic; usually NE after ganglion. Parasympathetic: CN III, VII, IX, X and S2–S4; long pre/short post; ACh at both synapses.

[SPECIAL SENSES] Explain: Eye tunics

Eye tunics: fibrous—sclera/cornea; vascular (uvea)—choroid/ciliary body/iris; neural—retina. Pupil is the opening in the iris.

[SPECIAL SENSES] Explain: Cornea is transparent and avascular

Cornea is transparent and avascular; sclera is tough white coat. Ciliary body and zonular fibers connect to lens; lens changes shape for accommodation. Conjunctiva lines inner eyelids and anterior sclera.

[SPECIAL SENSES] Explain: Anterior cavity contains aqueous humor

Anterior cavity contains aqueous humor; anterior chamber = cornea-to-iris; posterior chamber = iris-to-lens. Posterior/vitreous cavity behind lens contains vitreous humor.

[SPECIAL SENSES] Explain: Light

Light: cornea → pupil → lens → vitreous → retina. Rods—dim light/peripheral vision; cones—color/detail, concentrated in fovea. Optic disc has no rods/cones = blind spot.

[SPECIAL SENSES] Explain: Visual pathway

Visual pathway: optic nerve → optic chiasm (nasal retinal fibers cross; temporal fibers do not) → optic tract → lateral geniculate nucleus → optic radiations → occipital cortex. Chiasm compression may cause bitemporal hemianopia.

[SPECIAL SENSES] Explain: Pupil dilator = radial fibers/sympathetic/dilation

Pupil dilator = radial fibers/sympathetic/dilation; sphincter pupillae = circular fibers/parasympathetic/constriction.

[SPECIAL SENSES] Explain: Tear drainage

Tear drainage: lacrimal gland → eye surface → puncta → canaliculi → lacrimal sac → nasolacrimal duct → nasal cavity.

[SPECIAL SENSES] Explain: Hearing

Hearing: auricle → external acoustic canal → tympanic membrane → malleus → incus → stapes → oval window → cochlear fluid/hair cells → CN VIII. Ossicles: malleus-incus-stapes.

[SPECIAL SENSES] Explain: Semicircular canals detect angular rotation

Semicircular canals detect angular rotation; utricle and saccule detect linear acceleration and tilt. Smell: olfactory receptors → cribriform plate → bulb → tract → olfactory cortex.

[SPECIAL SENSES] Explain: Taste

Taste: anterior tongue 2/3 CN VII; posterior 1/3 CN IX; epiglottis region CN X. Touch receptors: Merkel—sustained pressure; Meissner—fine touch; Pacinian—vibration/deep pressure; Ruffini—stretch; free endings—pain/temp.

[ENDOCRINE SYSTEM] Explain: Endocrine glands release hormones into blood

Endocrine glands release hormones into blood. Example axis: hypothalamic TRH → anterior pituitary TSH → thyroid T3/T4 → increased cellular metabolism.

[ENDOCRINE SYSTEM] Explain: Infundibulum connects hypothalamus and pituitary

Infundibulum connects hypothalamus and pituitary. Posterior pituitary stores/releases hypothalamic hormones; anterior pituitary makes and releases its own hormones.

[ENDOCRINE SYSTEM] Explain: Posterior pituitary

Posterior pituitary: ADH/vasopressin—kidney water reabsorption; oxytocin—uterine contraction and milk ejection. Prolactin = milk production.

[ENDOCRINE SYSTEM] Explain: Anterior pituitary FLAT PiG

Anterior pituitary FLAT PiG: FSH, LH, ACTH, TSH, Prolactin, GH. FSH—follicle development/sperm production; LH—ovulation/testosterone; ACTH—adrenal cortex; TSH—thyroid; PRL—milk; GH—growth.

[ENDOCRINE SYSTEM] Explain: Pineal secretes melatonin for circadian rhythm

Pineal secretes melatonin for circadian rhythm. Thyroid follicular cells make T3/T4 (metabolism); C cells make calcitonin (lowers blood Ca). Parathyroid chief cells make PTH (raises blood Ca).

[ENDOCRINE SYSTEM] Explain: Hyperthyroidism

Hyperthyroidism: increased T3/T4, heat intolerance, weight loss, faster heart rate. Hypothyroidism: decreased T3/T4, cold intolerance, weight gain, slower heart rate/sluggishness.

[ENDOCRINE SYSTEM] Explain: Thymus—T-cell maturation

Thymus—T-cell maturation; thymosin. Pancreas: beta cells insulin ↓ glucose; alpha cells glucagon ↑ glucose; delta cells somatostatin; PP cells pancreatic polypeptide.

[ENDOCRINE SYSTEM] Explain: Type 1 diabetes

Type 1 diabetes: autoimmune beta-cell destruction and severe insulin deficiency. Type 2: insulin resistance with progressive impairment of insulin secretion.

[ENDOCRINE SYSTEM] Explain: Adrenal cortex outer-to-inner

Adrenal cortex outer-to-inner: Salt—aldosterone; Sugar—cortisol; Sex—adrenal androgens. Medulla—epinephrine/norepinephrine (Speed). Ovaries—estrogen/progesterone/inhibin; testes—testosterone/inhibin.

[HEART] Explain: Four chambers

Four chambers: RA, RV, LA, LV. Right side receives deoxygenated blood and sends it to lungs; left side receives oxygenated blood and sends it to body.

[HEART] Explain: Heart wall inside-to-outside

Heart wall inside-to-outside: endocardium → myocardium → epicardium (visceral pericardium). Pericardial fluid reduces friction; parietal serous and fibrous pericardium surround the heart.

[HEART] Explain: RA receives SVC, IVC, coronary sinus

RA receives SVC, IVC, coronary sinus. Pulmonary veins return blood to LA. Tricuspid = RA/RV, 3 cusps; mitral/bicuspid = LA/LV, 2 cusps; pulmonary and aortic = semilunar.

[HEART] Explain: Flow

Flow: body → SVC/IVC/coronary sinus → RA → tricuspid → RV → pulmonary valve → pulmonary trunk/arteries → lungs → pulmonary veins → LA → mitral → LV → aortic valve → aorta → body.

[HEART] Explain: Interatrial septum separates atria

Interatrial septum separates atria; interventricular septum separates ventricles. Pectinate muscles are in atria/auricles; trabeculae carneae are in ventricles.

[HEART] Explain: Papillary muscles pull chordae tendineae to prevent AV valve prolapse during…

Papillary muscles pull chordae tendineae to prevent AV valve prolapse during ventricular contraction; pressure differences close the valves. SA node → AV node → AV bundle/His → bundle branches → Purkinje fibers.

[HEART] Explain: Coronary arteries supply myocardium

Coronary arteries supply myocardium: right and left coronary arteries arise from aorta; LAD is a major left coronary branch. Coronary sinus drains myocardium to RA.

[BLOOD] Explain: Blood is fluid connective tissue

Blood is fluid connective tissue: plasma (liquid matrix) + formed elements. Approximate composition: plasma 55%, formed elements 45%; buffy coat = leukocytes + platelets.

[BLOOD] Explain: Formed element abundance

Formed element abundance: erythrocytes > platelets > leukocytes. RBCs are biconcave, lack nuclei when mature, and use hemoglobin to transport oxygen.

[BLOOD] Explain: Thrombocytes/platelets are megakaryocyte fragments involved in clotting/hemostasis

Thrombocytes/platelets are megakaryocyte fragments involved in clotting/hemostasis.

[BLOOD] Explain: Leukocytes defend against infection

Leukocytes defend against infection. Lecture sequence: neutrophils → lymphocytes → monocytes → eosinophils → basophils.

[BLOOD] Explain: Granulocytes

Granulocytes: neutrophils, eosinophils, basophils. Agranulocytes: lymphocytes, monocytes. Neutrophils—bacterial phagocytosis; lymphocytes—B/T/NK; monocytes—macrophage precursors; eosinophils—parasites/allergy; basophils—histamine/inflammation.

[ARTERIES] Explain: Arteries carry blood away from heart

Arteries carry blood away from heart. Aorta: ascending → arch → descending; thoracic aorta above diaphragm, abdominal aorta below.

[ARTERIES] Explain: Aortic arch branches right-to-left

Aortic arch branches right-to-left: brachiocephalic trunk (right common carotid + right subclavian), left common carotid, left subclavian.

[ARTERIES] Explain: Common carotid → internal carotid (brain) + external carotid (face/scalp/neck)

Common carotid → internal carotid (brain) + external carotid (face/scalp/neck); superficial temporal branches from external carotid. Vertebral arteries arise from subclavian and unite as basilar artery.

[ARTERIES] Explain: Circle of Willis is an alternate arterial route

Circle of Willis is an alternate arterial route. Classic ring includes anterior cerebral + anterior communicating + terminal internal carotids + posterior communicating + posterior cerebral arteries. Middle cerebral artery is not part of the ring.

[ARTERIES] Explain: Arm

Arm: subclavian → axillary (lateral border of first rib) → brachial → radial (lateral/thumb) + ulnar (medial/little finger) → palmar arches → digital arteries.

[ARTERIES] Explain: Leg

Leg: common iliac → external iliac → femoral (below inguinal ligament) → popliteal → anterior/posterior tibial; anterior tibial continues as dorsalis pedis.

[ARTERIES] Explain: Celiac trunk branches

Celiac trunk branches: left gastric, common hepatic, splenic. Superior mesenteric supplies much of midgut; inferior mesenteric supplies hindgut; renal supplies kidneys; gonadal supplies ovaries/testes.

[ARTERIES] Explain: Arterial wall

Arterial wall: tunica intima (inner endothelium), tunica media (smooth muscle/elastic), tunica externa/adventitia (connective tissue). Arteries generally have thicker media.

[VEINS] Explain: Veins carry blood toward heart

Veins carry blood toward heart. Internal jugular drains brain; external jugular drains superficial face/neck. Internal jugular + subclavian form brachiocephalic veins → SVC → RA.

[VEINS] Explain: Upper limb deep return

Upper limb deep return: digital/palmar → radial/ulnar → brachial → axillary → subclavian → brachiocephalic → SVC → RA.

[VEINS] Explain: Cephalic = superficial lateral arm

Cephalic = superficial lateral arm; basilic = superficial medial arm; median cubital connects them at elbow. Azygos drains much of thoracic wall to SVC.

[VEINS] Explain: Lower limb return

Lower limb return: tibial → popliteal → femoral → external iliac → common iliac → IVC. Great saphenous = medial superficial leg → femoral; small saphenous = posterior leg → popliteal.

[VEINS] Explain: Portal route

Portal route: superior mesenteric + splenic veins (inferior mesenteric usually joins splenic) → hepatic portal vein → liver sinusoids → hepatic veins → IVC. Portal enters liver; hepatic veins leave liver.

[VEINS] Explain: Right gonadal vein usually drains directly to IVC

Right gonadal vein usually drains directly to IVC; left gonadal vein commonly drains to left renal vein. Renal veins drain kidneys; hepatic veins drain liver.

[VEINS] Explain: Clinical

Clinical: thrombus stays in one place; embolus travels. Immobility reduces skeletal muscle pump activity and promotes venous stasis. DVT may travel femoral → external iliac → common iliac → IVC → RA → RV → pulmonary arteries, causing pulmonary embolism.

[VEINS] Explain: Arterial blockage reduces oxygen delivery → ischemia → possible necrosis

Arterial blockage reduces oxygen delivery → ischemia → possible necrosis; may cause cold skin and pain. Venous blockage causes pooling, swelling, and increased pressure.

[RESPIRATORY SYSTEM] Explain: Airway

Airway: nares → nasal vestibule → nasal cavity → nasopharynx → oropharynx → laryngopharynx → larynx → trachea → carina → primary/main bronchi → secondary/lobar → tertiary/segmental bronchi → bronchioles → terminal bronchioles → respiratory bronchioles → alveolar ducts/sacs → alveoli.

[RESPIRATORY SYSTEM] Explain: Pharynx

Pharynx: nasopharynx (air), oropharynx (air/food), laryngopharynx (air/food). Hard palate is anterior roof; soft palate ends in uvula and helps close nasopharynx during swallowing.

[RESPIRATORY SYSTEM] Explain: Hyoid is a bone below mandible

Hyoid is a bone below mandible. Thyroid cartilage is larger/superior; laryngeal prominence = Adam's apple; cricoid cartilage is smaller/inferior. Epiglottis helps prevent aspiration.

[RESPIRATORY SYSTEM] Explain: Glottis = vocal cords/folds plus space between them

Glottis = vocal cords/folds plus space between them; vocal cords alone are the folds. Trachea has C-shaped cartilage open posteriorly toward esophagus. Carina is tracheal bifurcation.

[RESPIRATORY SYSTEM] Explain: Right main bronchus is wider, shorter, and more vertical, so aspirated material…

Right main bronchus is wider, shorter, and more vertical, so aspirated material more often enters right lung. Right lung: 3 lobes (superior/middle/inferior), horizontal + oblique fissures. Left lung: 2 lobes, oblique fissure, cardiac notch.

[RESPIRATORY SYSTEM] Explain: Visceral pleura adheres to lung

Visceral pleura adheres to lung; parietal pleura lines thoracic wall/diaphragm/mediastinum; pleural fluid reduces friction.

[RESPIRATORY SYSTEM] Explain: Conducting zone ends at terminal bronchioles

Conducting zone ends at terminal bronchioles. Respiratory zone begins at respiratory bronchioles and includes alveolar ducts, sacs, alveoli. Type I pneumocytes exchange gas; Type II pneumocytes secrete surfactant.

[RESPIRATORY SYSTEM] Explain: Gas exchange occurs at alveoli across the alveolar-capillary membrane

Gas exchange occurs at alveoli across the alveolar-capillary membrane. Pulmonary arteries carry deoxygenated blood to lungs; pulmonary veins return oxygenated blood to left atrium.

[RESPIRATORY SYSTEM] Explain: Inspiration

Inspiration: diaphragm contracts/descends → thoracic volume increases → intrapulmonary pressure decreases → air enters. Phrenic nerve = C3–C5. Quiet expiration is mostly passive; forced expiration uses internal intercostals and abdominal muscles.

[RESPIRATORY SYSTEM] Explain: Three structures through diaphragm

Three structures through diaphragm: esophagus, IVC, aorta. Hiatal hernia occurs when part of stomach moves superiorly through esophageal hiatus; professor linked it with heartburn.

[RESPIRATORY SYSTEM] Explain: Nasal turbinates

Nasal turbinates: superior, middle, inferior. Sinuses: frontal, ethmoid, sphenoid, maxillary. Professor identified frontal and sphenoid in midsagittal view; some sinuses are lateral and not visible in that section.

[LYMPHATIC SYSTEM] Explain: Lymph begins as interstitial fluid entering blind-ended lymphatic capillaries →…

Lymph begins as interstitial fluid entering blind-ended lymphatic capillaries → collecting lymphatic vessels (valves) → lymph nodes → trunks → ducts → venous angles.

[LYMPHATIC SYSTEM] Explain: Lymph returns near the junction of internal jugular and subclavian veins

Lymph returns near the junction of internal jugular and subclavian veins. Skeletal muscle contraction, breathing, and valves move lymph; there is no central heart-like pump.

[LYMPHATIC SYSTEM] Explain: Right lymphatic duct drains right head/neck, right thorax, and right upper limb…

Right lymphatic duct drains right head/neck, right thorax, and right upper limb (right upper quadrant). Thoracic duct drains the rest of the body, including both lower limbs and left upper quadrant; it begins near cisterna chyli and empties at left venous angle.

[LYMPHATIC SYSTEM] Explain: Primary lymphoid organs

Primary lymphoid organs: red bone marrow (blood-cell formation/B-cell development) and thymus (T-cell maturation). Secondary: lymph nodes, spleen, tonsils, MALT/appendix.

[LYMPHATIC SYSTEM] Explain: Lymph nodes filter LYMPH

Lymph nodes filter LYMPH; spleen filters BLOOD. Afferent lymphatic vessels enter the convex surface of a node; efferent vessel exits at the hilum.

[LYMPHATIC SYSTEM] Explain: Tonsils

Tonsils: pharyngeal/adenoids—nasopharynx; palatine—sides of oropharynx; lingual—base of tongue.