Lecture 10: Cranial Nerves PDF

Concentrated in FOVEA CENTRALIS of MACULA LECTURE 10 LUTEA CRANIAL NERVES Important topics in the exam: Lots of questions Olfactory nerve – CN I (SENSORY) o Foramen of exit is CRIBRIFORM PLATE of ETHMOID BONE...

Concentrated in FOVEA CENTRALIS of MACULA LECTURE 10 LUTEA CRANIAL NERVES Important topics in the exam: Lots of questions Olfactory nerve – CN I (SENSORY) o Foramen of exit is CRIBRIFORM PLATE of ETHMOID BONE o o Fovea centralis – contains greatest amount of CONES ▪ As it approaches the periphery, cones decrease in number ▪ Light passes through the lens, and the lens tries to focus it towards the Fovea Centralis o Macula lutea – yellowish area near the center of retina that contains fovea centralis C-C-C (Cones – Color -> Fovea Centralis) ▪ THREE TYPES OF CONES: RGB Cribriform – meaning “porous” o Remember: Rainbow = ROYGBIV o The SHORTEST cranial nerve ▪ Also is the VISIBLE LIGHT o Sense of Smell – SENSORY SPECTRUM Optic Nerve – CN II – (SENSORY) o Red – Helps with color red, as well as o Foramen of exit is OPTIC CANAL orange and yellow with green ▪ Two important structures that pass through the OPTIC ▪ TRIVIA: RED CONES are the first CANAL cones formed Optic Nerve o Blue – Helps with color blue, and even Ophthalmic Artery indigo and violet o coming from Internal Carotid Artery o Green – Helps with color green, as well o Sense of Sight - SENSORY as the orange and yellow with red o PHOTORECEPTORS of the EYE o Ultraviolet and Infrared ▪ Detects PHOTONS, has two types: ▪ Colors that the human eye does ▪ Cones – Color (Letter “C” Cones for Color) not have the cones to see Photopigment – OPSIN Colorblindness Characteristic: o Depends of which of the RGB cones are o Less sensitive to light absent/defective ▪ Means they are not easily ▪ Example: Absent red cones will stimulated cause red and the red elements ▪ Sufficient light within the of the orange and yellow environment must be present o Mostly only affects ONE cone, TWO or o High visual acuity more is rare ▪ Means it is Very Clear ▪ When there is sufficient light, there is high detail that can be observed from colors by the cones  ▪ ii. Rods – Black to Gray Responsible for NIGHT VISION Oculomotor Nerve – CN III (MOTOR) Photopigment – Rhodopsin o Foramen of exit is SUPERIOR ORBITAL FISSURE (SOF) Characteristic: ▪ CN that exits through SOF o Very sensitive to light CN 3, 4, V1, and 6 ▪ Even if there is very little light, o Innervates MOST EXTRINSIC MUSCLE OF THE EYE Rods function well ▪ CN III is MOTOR o Low visual acuity o Carries PARASYMPATHETIC neurons to IRIS SPHINCTER ▪ Tradeoff, things are less clear ▪ Causes PUPIL CONSTRICTION (or Miosis) Concentrated AWAY from FOVEA CENTRALIS o SIDENOTE: Only 4 Cranial Nerves contain PARASYMPATHETIC o Found more in the periphery Neurons o Basic parts of the eye ▪ CN 3 – Pupillary Constriction ▪ Lens – concentrates the light to the Retina ▪ CN 7 – To 3 glands Cataracts – caused by a defective lens, usually Lacrimal Glands – produce TEARS CLOUDY LENS Submandibular Gland – produce Saliva ▪ Cornea – transparent portion in front of the eye Sublingual Gland – produce Saliva Has a specific shape in order to properly ▪ CN 9 – Parotid Gland – produce saliva reflect/refract the light ▪ CN 10 – Organs in Trunk; specifically in the THORACIC and Astigmatism – caused by abnormal shape of the ABDOMINAL regions cornea Thoracic Cavity – Heart, Lungs, Esophagus o Which results in light flares Abdominal Cavity – Stomach, Intestines, ▪ Retina – where image is formed Pancreas, Liver, and Kidneys ▪ Iris – gives color to the eye o REMEMBER: Extrinsic Muscles of the Eye (SO4 LR6 R3) Contains epithelium that has MELANIN, which ▪ A. Superior oblique – moves eyeballs INFERIORLY and results in the black/brown color LATERALLY o More in Asians and those nearer the ▪ B. Lateral rectus – moves eyeballs LATERALLY equator ▪ C. Superior rectus – moves eyeballs SUPERIORLY ▪ Sclera – white portion of the eye ▪ D. Inferior rectus – moves eyeballs INFERIORLY ▪ Pupil – constricts and dilates depending on the situation ▪ E. Medial rectus – moves eyeballs MEDIALLY ▪ Aqueous humor – fluid on the anterior part of the eye ▪ F. Inferior oblique – moves eyeballs SUPERIORLY and Canal of Schlemm – drainage of the aqueous LATERALLY humor ▪ G. Levator palpebrae superioris – ELEVATES EYELIDS Glaucoma – blockage of Schlemm’s Canal, ▪ NOTE: First word determines what DIRECTION the causing intraocular pressure. Causes tunnel muscle moves the muscle vision (Let ChatGPT Explain) The two oblique muscles are exceptions; they ▪ Vitreous humor – fluid on the posterior part of the eye pull to the OPPOSITE side and LATERALLY ▪ Optic disc – are where no cones or rods are present ▪ MNEMONIC FOR EXTRINSIC MUSCLE CN INNERVATION Point in retina where OPTIC nerve enters towards SO4 – Superior Oblique | Cranial Nerve IV the eye LR6 – Lateral Rectus | Cranial Nerve VI Also known as the BLIND SPOT R3 – Rest of the muscles | Cranial Nerve III o However, the other eye can see the Blind Spot, so if both are working, blind spot is TROCHLEAR NERVE – CN IV (MOTOR) usually minimal o Foramen of exit is SOF o Fun exercise: Try the blind spot test o Innervates the SUPERIOR OBLIQUE MUSCLE o QUESTION: What is OD, OS, and OU? o Longest INTRACRANIAL nerve ▪ OD – Oculus Dexter; medical term for RIGHT eye o Smallest Cranial Nerve ▪ OS – Oculus Sinister; medical term for LEFT eye ▪ OU – Oculus Uterque; medical term for BOTH eyes  TRIGEMINAL NERVE – CN V (MIXED) o Motor and Sensory (Mixed) o BOARD EXAM: Arises from 4 Nucleus in the CNS ▪ Mesencephalic Nuclei ▪ Principal Sensory ▪ Spinal Nucleus ▪ Motor Nucleus o 3 Divisions ▪ Ophthalmic – CN V1 Foramen of exit is SUPERIOR ORBITAL FISSURE SENSORY in function BOARD EXAM: Two Important Branches: o FRONTAL Nerve – Largest V1 branch o LACRIMAL Nerve – Smallest V1 branch ▪ Lacrimal Nerve of CN V1 is only o SENSORY, does not cause tear secretions ▪ It is actually CN VII that has the Parasympathetic innervation of Lacrimal Nerve ▪ Maxillary – CN V2 Foramen of exit is FORAMEN ROTUNDUM SENSORY in function Has many branches: ▪ Nasopalatine Nerve / Long Sphenopalatine Mainly named as TRIGEMINAL GANGLION Nerve (aka NERVE of SCARPA) o Also called as SEMILUNAR GANGLION or o Exits in Incisive Foramen GASSERIAN GANGLION o Is NOT known as the INCISIVE NERVE o Innervates Palate from CANINE TO CANINE o Innervates ANTERIOR 1/3 of the Hard Palate (Canine to Canine) Greater Palatine Nerve / Anterior Palatine Nerve o Exits in the GREATER PALATINE FORAMEN o Innervates POSTERIOR 2/3 of Hard Palate ▪ Confusing because it says “Anterior Palatine Nerve” although it innervates the o POSTERIOR 2/3 of Hard Palate ▪ BOARD EXAM: What is the cutaneous (skin) innervation Lesser Palatine Nerve / Posterior Palatine Nerve of the tip of the nose? o Exits in the LESSER PALATINE FORAMEN CN V1 – Ophthalmic Division of Trigeminal Nerve o Innervates the Soft Palate o Not the CN VII or Facial Nerve o CN VII usually innervates the UNDERLYING MUSCLES So CN V1 is skin/cutaneous, CN VII is underlying o Largest CRANIAL nerve  Posterior Superior Alveolar Nerve (PSAN) o Anterior Division - Smaller division. Mainly motor; has 1 sensory o Innervates soft tissue and teeth of: branch; Anterior Division innervates the Muscles of Mastication ▪ Max 2nd and 3rd Molars ▪ Anterior and Posterior Deep Temporal Nerve – MOTOR (including all roots) “Temporal” as in Temporalis ▪ Max 1st molar (DB and Palatal Temporalis Muscle – Motor Root) o O: Temporal Bone Middle Superior Alveolar Nerve (MSAN) o I: Coronoid Process o Innervates soft tissue and teeth o A: Anterior – Elevate Mandible ▪ Max 1st Molar (MB root) o A: Posterior – Detrudes Mandible ▪ Max 1st and 2nd Premolar ▪ Medial Pterygoid Nerve – MOTOR Anterior Superior Alveolar Nerve (ASAN) Internal Pterygoid Muscle o Innervates soft tissue and teeth o O: Medial of Lateral Plate of Sphenoid ▪ Max Anteriors o I: Medial angle of Mandible Infraorbital Nerve o A: Elevates Mandible o Exits through INFRAORBITAL FORAMEN ▪ Masseteric Nerve – MOTOR o Innervates SOFT TISSUE ONLY: Masseter Muscle ▪ Skin of lower eyelid o O: Zygomatic bone ▪ Skin of upper lip o I: Ramus of the Mandible ▪ Ala of the nose o A: Elevates the Mandible o BOARD EXAM: What tooth is used as ▪ Lateral Pterygoid Nerve – MOTOR the landmark for Infraorbital Nerve External Pterygoid Muscle Block? o O: Lateral Portion of Lateral Plate of ▪ Canine or 1st Premolar Sphenoid ▪ However, in a true or false o I: Condyle/Neck of Condyle situation, answer varies from o A: Depresses Mandible; side-to-side CENTRAL INCISOR to 2ND PM ▪ Long Buccal Nerve – SENSORY o BOARD EXAM: Infraorbital Nerve gives Innervates the MUCOPERIOSTEUM of rise to the ASAN and MSAN Mandibular Molars o Posterior Division – LARGER division and MAINLY sensory; with 1 motor branch ▪ Mylohyoid Nerve – MOTOR Innervates the MYLOHYOID muscle and Anterior Belly of Digastric Muscle ▪ o V3 innervates MYLOHYOID and Anterior o BOARD EXAM: Other name for Belly of Digastric Muscle Infraorbital Nerve Block? ▪ Inferior Alveolar Nerve – SENSORY ▪ True ASAN Block Largest branch of the mandibular nerve o BOARD EXAM: Most common Innervates all mandibular teeth (via IAN and complication in Infraorbital Nerve Incisive Nerve) and Gingiva from PM going Block? anteriorly to Midline (via Mental Nerve) ▪ Ecchymosis or Hematoma Terminates into: ▪ Hematoma is best answer o Mental Nerve: Mandibular – CN V3 *****Type in Stuff from Book Here****** ▪ Chin, Lip, Facial Gingiva, Mucosa o Foramen of exit is FORAMEN OVALE from 2nd Premolar Anterior o SENSORY and MOTOR (MIXED) – Only CN V branch with MOTOR o Incisive Nerve neurons ▪ Mandibular Teeth and o LARGEST branch of Trigeminal Nerve Periodontal Ligaments from 1st o Has 2 Divisions: PM anteriorly (depends on  location of branching of IAN of Vagus Nerve – Internal Laryngeal Nerve; base of the tongue (Gen and Mental and Incisive nerve) Taste) ▪ Auriculotemporal Nerve – SENSORY (BOARD BOARD EXAM: Other branches of V3 IMPORTANT) o Meningeal Nerve TMJ ▪ Goes to the MENINGES, specifically the DURA MATER Sensory innervation of PAROTID GLAND o Tensor Veli Palatini Nerve o BOARD QUESTION: What is the sensory ▪ Innervates the Tensor Veli Palatini Muscle (CN V3) innervation of the Parotid Gland? o Tensor Tympani Nerve ▪ Answer: Auriculotemporal ▪ Innervates the Tensor Tympani Muscle Nerve ▪ BOARD EXAM: Tensor Tympani Muscle is attached to Scalp in TEMPORAL region what bone? ▪ Lingual Nerve – SENSORY MALLEUS General sensation in ANTERIOR 2/3 of tongue Sturge-Weber Syndrome (aka Encephalotrigeminal Angiomatosis) Sensory innervation of gingiva and mucous o Triad: membrane on the LINGUAL SIDE of ▪ Port-wine Stain MANDIBULAR TEETH Seen in many diseases ▪ Eye diseases (such as Glaucoma) ▪ Neurological Disorder BOARD SIDENOTE: Sensory innervations of the tongue Tongue (Tongue Proper) has 2 main divisions: o Anterior 2/3 of tongue ▪ General Sensation – CN V3 (Lingual Nerve) ▪ Taste Sensation – CN VII (Chorda Tympani Nerve) o Posterior 2/3 of tongue ▪ General and Taste sensation – CN IX o Root of Tongue ▪ Gen and Taste – CN X o Tongue has 4 Cranial Nerves involved o o Port-wine Stain (in Sturge-Weber Syndrome) ▪ Follows CN V, specifically V1 and V2 Trigeminal Neuralgia (aka Tic Douloureux) o Trigeminal Nerve fires abnormal signals, causing pain o BOARD EXAM: Treatment for Trigeminal Neuralgia? ▪ Carbamazepine (brand name: Tegretol) Anti-seizure drug Some cases present with drug resistance, lowering effectivity over time ▪ Local Anesthesia Bupivacaine is recommended because it has the o LONGEST DURATION of anesthesia (8-12 hours) REMEMBER: Mandibular Nerve – Lingual Nerve; Anterior 2/3 of Tongue (General) Facial Nerve – Chorda Tympani Nerve; Anterior 2/3 of Tongue (Taste) Glossopharyngeal Nerve – Posterior 1/3 of Tongue (General and Taste) CONTINUATION OF CRANIAL NERVES o Made up of two parts: ▪ Vestibular Nerve and Cochlear Nerve merge to form this ABDUCENS NERVE – CN VI (MOTOR) nerve o Foramen of exit is SOF ▪ Vestibular Nerve – Helps with BALANCE (V for VALANCE) o Innervates the LATERAL RECTUS OF THE EYE (only function) ▪ Cochlear Nerve – For HEARING o Problems with this nerve may cause VERTIGO and HEARING FACIAL NERVE – CN VII (MIXED) problems o Foramen of exit is STYLOMASTOID FORAMEN o Basic Parts of the Ear: o Branches: ▪ Outer Ear (Important) o Extracranial Branches: AFTER EXITING Stylomastoid Foramen Auricle/Pinna – Elastic Cartilage ▪ Auricular Nerve – Controls SCALP muscles around ear Ear Canal Only function Ear Drum / Tympanic Membrane ▪ Branch to Posterior Belly of Digastric Muscle o Vibrations are transmitted from air to ▪ Branch to Stylohyoid Muscle the Malleus ▪ IMPORTANT: 5 Major Branches in Parotid Gland o As the Malleus vibrates, it vibrates the Temporal Incus, and passes it to the Stapes Zygomatic ▪ Middle Ear Buccal Malleus Mandibular Incus Cervical Stapes ▪ Inner Ear Cochlea – Snail shaped organ in our ear o Organ of Corti – Receptor organ for hearing ▪ o BOARD IMPORTANT: ▪ Hair Cells – sensory receptors for hearing Hair cell = Hear Cells o Intracranial Branches: BEFORE EXITING the Stylomastoid Semicircular Canals Foramen o Contains SEMICIRCULAR FLUID for ▪ Chorda Tympani balance Taste sensation in Anterior 2/3 of Tongue o Connected to the Vestibular Nerve Submandibular Gland (Parasympathetic/Motor) o Trivia: Hearing is the LAST SENSE that is lost before death Sublingual Gland (Parasympathetic/Motor) ▪ Greater Petrosal Nerve GLOSSOPHARYNGEAL NERVE – CN IX (MIXED) Parasympathetic/Motor to LACRIMAL GLAND o Foramen of exit: JUGULAR FORAMEN (Tears) ▪ Three CN that exit the jugular foramen CN 9, 10, and 11 VESTIBULOCOCHLEAR NERVE – CN VIII (SENSORY) o Innervates: o Foramen of exit is INTERNAL ACOUSTIC MEATUS ▪ Parotid Gland – Parasympathetic o Responsible for sense of hearing – sensory ▪  ▪ Tongue ▪ Physiologically, you cannot General and Taste sensation to posterior 1/3 of self-sabotage your own tongue lungs ▪ Forms part of the PHARYNGEAL PLEXUS (CN IX and X) ▪ Pharyngeal Plexus (IX and X) Pharyngeal Plexus - innervates MOST MUSCLE of ▪ Gag Reflex – MOTOR PALATE and PHARYNX ▪ Base of the Tongue – General Taste and sensation ▪ Gag Reflex – Sensory BOARD EXAM: Gag reflex has SENSORY and SPINAL ACCESSORY NERVE (ACCESSORY NERVE) CN XI (MOTOR) MOTOR o Unique feature: Only Nerve the ENTERS and EXITS the skull o Sensory – CN IX ▪ Enter: Foramen Magnum o Motor – CN X ▪ Exit: Jugular Foramen ▪ It is a Cranial Nerve not because it arises there, but because it enters the cranium, and then exits it SIDENOTE: Autonomic (Sympathetic and Parasympathetic NS is always o MOTOR - Branches: MOTOR) ▪ Sternocleidomastoid SIDENOTE: Pharyngeal Plexus ▪ Trapezius – Rotates chin to opposite side of the body BOARD QUESTION Pharyngeal Plexus innervates MOST muscles of PALATE and PHARYNX HYPOGLOSSAL NERVE – CN XII (MOTOR) o Palato or Palati – Muscles relating to palate o Exit: Hypoglossal Canal o Pharyng – Muscles relating to the pharynx o Innervates MOST EXTRINSIC MUSCLE OF TONGUE BOARD EXAM: If a question asks which CN is involving the Pharyngeal ▪ Except the PALATOGLOSSUS (IX AND X) Plexus (IX and X) ▪ Genioglossus (CN XII) – moves tongue inferiorly and o Answer: Safest answer is X (Vagus) anteriorly o EXCEPTION: Tensor Veli Palatini: Innervated by the CN V3 ▪ Styloglossus (CN XII) – Moves tongue superiorly and o EXCEPTION: Stylopharyngeus posteriorly ▪ Innervated by CN IX ▪ Hyoglossus (CN XII) – Moves tongue inferiorly ▪ Because it arises from CN IX before reaching the o Innervates: ALL INTRINSIC MUSCLE OF TONGUE (MOTOR) plexus QUESTION: VAGUS NERVE – CN X (MIXED) o Known as the WANDERING NERVE What are the cranial nerves with PARASYMPATHETIC innervation? ▪ Arises from the brainstem and goes to the heart, the o CN III, CN VII, CN IX, and CN X (CN 3, 7, 9, and 10) lungs, the urinary system, etc ▪ CN III – Miosis ▪ Also why it is called as the LONGEST CRANIAL NERVE ▪ CN VII – LSS o Exit: JUGULAR FORAMEN ▪ CN IX – P o Innervates: ▪ CN x – Organs ▪ Organs – Parasympathetic Altered lacrimation is associated in damage of what cranial nerve? Heart, Lungs, Digestive Tract, Kidney, Liver, o Answer: CN VII (specifically, the Greater Petrosal Nerve) etc. – Parasympathetic Innervation o CN V2 (second best answer) Lungs – Responsible for the Herring-Bruer ▪ Because CN V2 has a part that is close to the CN VII, Reflex and if CN V2 has tumor or enlargement, it may crush o Herring-Bruer Reflex – Prevents or affect CN VII. over-inflation of lungs Vitamin K-Dependent Clotting Factors produced by the liver are? ▪ Lungs have stretch receptors o Answer: Clotting Factors 2, 7, 9, 10 ▪ Activated when lung has ▪ Put here because its number is close to the reached capacity, to stop the PARASYMPATHETIC Cranial Nerves inhalation process ▪ Remember: Parasympathetic Cranial Nerves: 3, 7, 9, 10  ▪ Vitamin K-Dependent Clotting Factors (replace 3 with ▪ The fibrin meshing with the platelet plug determines the 2) CLOTTING TIME Clotting Factors 2, 7, 9, and 10 How is fibrin formed? o Clotting Factors o Through the CLOTTING FACTORS and the COAGULATION ▪ I – Fibrinogen CASCADE (Doc Sia discussion) ▪ II – Prothrombin o Coagulation Cascade Pathways: ▪ III – Thromboplastin (Tissue Factor) ▪ Intrinsic Pathway ▪ IV – Calcium ▪ Extrinsic Pathway ▪ V – Labile Factor ▪ Common Pathways ▪ VI – (Not yet approved) o Coagulation Cascade ▪ VII – Stable Factor ▪ Intrinsic Pathway (TENET – Twelve, Eleven, Nine, Eight, ▪ VIII – Antihemophilic Factor Ten) Hemophilia A Factor XII o Most important clotting factor o Coming from the liver, is present in o Caused by deficiency in Factor 8 circulation ▪ IX – Christmas Factor o Once Platelets (Platelet Plug) and Hemophilia B Enzymes are formed, they activate o Caused by deficiency in Factor 9 Factor XII ▪ X – Stuart Factor Factor XIIa ▪ XI – Plasma Thromboplastin Antecedent o Activates Factor XI Hemophilia C Factor XIa o Caused by deficiency in Factor 11 o Activates Factor IXa ▪ XII – Hagemann Factor Factor IXa ▪ XIII – Fibrin Stabilizing Factor o Activates Factor VIII Factor VIIIa CLOTTING PATHWAY o Activates Factor Xa Blood Clot Common pathway occurs o Made of FIBRIN and PLATELETS ▪ Extrinsic Pathway (3 + 7 = 10) Bleeding Time Extrinsic Factor is only activated when there is o Time it takes before a bleeding stops Injury (Why Extrinsic Pathway is the START of the o Usually in small bleedings (needle injury) coagulation cascade) ▪ Normal time in a needle injury is 1-3 minutes Factor III Clotting Time o Present in the BLOOD VESSEL WALLS o Time it takes before a clot is formed o Activates Factor VII o Normal range: 6-8 minutes / 8-15 minutes Factor VIIa ▪ Around 8 minutes o Activates Factor X Is clotting always required to stop bleeding? Common Pathway Occurs o Not always ▪ Common Pathway So what happens? Factor Xa (a = activated) o In an injury, when there is an injury, the first reaction comes from o Has subordinates: the PLATELETS ▪ Factor IV and V activate factor X o Platelets form the PLATELET PLUG, which initially stops the o Once Factor X is activated, it stimulates bleeding Factor II (Prothrombin) from the Liver ▪ Formation of the PLATELET PLUG determines the Factor II (Prothrombin) BLEEDING TIME o Needs to be activated by Factor X to o In around 8 minutes, Fibrin strands are formed and meshes with become THROMBIN the Platelet Plug, forming then the CLOT Factor I (Fibrinogen) ▪ Clot is composed of Fibrin and Platelets o Needs to be activated by Factor II to become FIBRIN  Factor XIII (Fibrin Stabilizing Factor) ▪ P – Nine, T- Thirteen o Needs to be activated by THROMBIN to QUESTION: What measures the Intrinsic Pathway? stabilize the fibrin o Why are Clotting Factors named in seemingly random numbers? Answer: Partial Thromboplastin Time (PTT) (Play Table Tennis = ▪ They are named in order of when they were discovered Indoor = Intrinsic) o What happened to Factor VI? o Normal value: 25s-35s ▪ Still unsure of its role, but it is present ▪ Reversed, it is PTT is TTP Hemophilia – Bleeding Disorder TTP = TwenTy Payb o Three Types: A, B, and C TTP = ThirTy Payb ▪ Hemophilia A (A = 8) Most common Hemophilia QUESTION: Which clotting factors do not come from the Liver? Male predilection (Maybe X-linked recessive Answer disorder) o Factor III – comes from Endothelial Cells (lining of vessels) o XX and XY ▪ That’s why it activates the extrinsic pathway, when o Both X must have the Hemophilia gene vessels are injured o However, in males, we only have one X, ▪ However, it is also released by Mononuclear Cells and no backup X gene o Factor IV – Calcium. This factor is found in our diet/food Caused by deficiency in Factor VIII ▪ Board exam: Among the following electrolytes, o Involves INTRINSIC PATHWAY which is important for clotting? ▪ Hemophilia B (Benign = B = 9) Calcium Caused by deficiency in Factor IX o Factor VIII – comes from the SINUSOIDAL cells of the liver and o Christmas factor because discovered by as well as ENDOTHELIAL Cells someone named Christmas ▪ Most cells come from the HEPATOCYTES of LIVER o Also involves INTRINSIC PATHWAY ▪ Factor VIII comes from the SINUSOIDAL CELLS of liver ▪ Hemophilia C (C-eben Eleven) Caused by deficiency in Factor XI QUESTION: Which clotting factors Vitamin-K dependent? o Also involves INTRINSIC PATHWAY Answer: 2, 7, 9, 10 Self-note: review the video on Coagulation Cascade ▪ o Hemophilia – Normal BT, Increased CT ▪ Affects fibrin formation, not platelet formation QUESTION: What measures the Extrinsic Pathway? Answer: Prothrombin Time (PT) (Play Tennis = Outdoor = Extrinsic) o Measures how fast prothrombin is formed o Normal value is: 9s-13s ▪ P looks like 9