Exam #3

brain #2, ANS, Blood, Heart

Effectors

Autonomic NS and innervation

Sympathetic

Parasympathetic

• Preganglionic Neurons – Cell bodies originate in the CNS

• Postganglionic Neurons – Cell bodies found at ganglia

Parasympathetic Division

maintain homeostasis (stable internal enviro)

fx: Slows heart rate, increases digestive fxs, controls sphincters of digestive,

urinary, and reproductive systems. Constricts pupils

Preganglionic neurons:

• Long (axons)

• Secrete acetylcholine (ACh) as a neurotransmitter (cholinergic)

• Arise from cranial and sacral regions

• A.K.A. “Cranio-sacral division”

• Cranial = CN III, V, VII, IX, X; Sacral = S2-S4

• The Vagus nerve (CN X) – one of the most important psym nerves (innervates heart, lungs,

stomach, intestines, other viscera)

Postganglionic neurons:

• Short (axons)

• Also secrete ACh

Sympathetic Division

response to emergencies or stress

fx: Increases heart rate, shunts blood toward skeletal mms, increases respiration rate. Dilates pupils

Preganglionic neurons

• Short (axons)

• Secrete acetylcholine (ACh) as a neurotransmitter.

• Arise from thoracic/lumbar regions

• A.K.A. “sympathetic trunk”

• T1-L2

• Synapse with postganglionics at Sympathetic Chain Ganglia

Postganglionic neurons:

• Long (axons)

• Secrete norepinephrine/noradrenaline (adrenergic).

also innervates the adrenal medulla which releases epinephrine (adrenaline)

blood Fx

• Transportation - oxygen and carbon dioxide as well as nutrients and waste products

• Regulation - body temperature, pH, and fluid volume

• Protection - by mounting an immune response and the production of antibodies

composition of blood

erythocytes: 44% = hematocrties

Buffy Coat: 1% (WBC and Platelets)

Plasma: 55%

Blood Plasma Composition

water 92%

plasma proteins 7%

• albumin 58%

• globulins 37%

• fibrinogen 4%

• regulatory proteins 1%

other 1%

• nutrients, respiratory gases, wastes

Hematocrit

% of the volume of all formed elements in ones blood (primarily RBC)

female: 38-45%

males: 40-50%

Erythocytes

• not true cells, no organelles, no nucleus

• 7.5 um. biconcave to increase SA

• rouleau - line up like a stack of coins in capillaries

Hemoglbin in erythocytes

• 280 per rbc

• reversible binding to 4 O2 or 4 CO2

• heme: ringed moleucle with iron ion

Erythopoiesis

creation of RBCs/erythrocytes @ red marrow

• 120 day cycle

• erythropoietin (EPO) = hormone produced by kidneys low o2. stimulates erythopoiesis

3 mill a sec. 200 billion a day. 25 trillion total

recycling aged or damaged erythocytes

aged erythocytes gets phagocytized in liver and spleen

-recycled heme (without Fe) turnin into bile from liver

-Fe is transported ad stored in liver

-proteins are borken down into amino acids which can make new erythocytes

Doped blood

rbc from donor or previously removed

or the homrone EPO is injected

• muscles work longer and harder wout cramping

Leukocytes

true cells: nucleus and organelles

“buffy coat”

initiate immune response

1.5 to 3 times larger than erythocytes

• diapedesis: leaving bv to enter tissues

• chemotaxis: attraction to site of infection/damage by chemicals

Classification of Leukocytes

granulocytes (visible granules)

• Neutrophils 50-70% (baceterial fungal)

• Eosinophils: 1-4% (allergens, parasites)

• Basophils: 0.5-1% (release histamine in inflammation)

Agranulocytes

• lymphocytes: 20-40% (activate b and t cells against viruses, tumors, adaptive, immune responses return to normal fx)

• monocytes: 2-8% (migrate from blood, form mmacrophages, target bacteria, tumor cells)

platelets (thrombocytes)

fragments of large cells = megakaryoctyes (15x)
¼ size of erythocytes

clotting of blood when exposed to collagen

• fibrin provides meshwork of clot

Blood Clot

hemopoiesis

formed elements (rbcs, platelets) short life span

• occurs in red marrow

• hemocytoblasts = stem cells (pluripotent)

• two lines of dev

  • myeloid = erythocytes, (erythopoiesis) megakaryocyes (thrombopoiesis), all leukocytes (leukopoiesis)

  • lymphoid = lymphocytes exception (b and t lymphoblast)

Pulmonary vs Systemic Circuit

one pump directs blood to lungs (right)

one pumps directs blood to most body tissues (left)

blood pressure

force of the blood on walls of arteries

• normal 120/80mmHg

Pericaridum

• within mediastinum
  fibruos pericardium: outer covering (dense irrct)

• serous pericardium

  • parietal and visceral (epicardium)

  • pericardial cavity and pericardial fluid

pericarditis vs pericardial effusion

-inflammation of the pericardium

-fluid accumulates around heart

heart wall

epicardium - areolar ct

myocardium - thickest

endocardium - internal surface of heart chambers and external of heart valves

coronary sulcus

Right Atrioventricular (tricuspid)

• forced closed when ventricle begins to contract (increases pressure)

• then after ventricle into: pulmonary semilunar valve

coronary circulation

• right and left coronary arteries are only branches off ascending aorta

• right

  • marginal (r border)

  • posterior interventricular artery

• left

  • anterior interventircular arteris

  • circumflex artery: left atrium and vent

Coronary veins

great cardiac vein: anterior interventircular a

middle cardiac vein: posterior interventricular A.

small cardiac vein: to R marginal a.

gap junctions

comprised as intercalated discs

work as single unit

funcitonal syncytium = mechanical/chemical linkage

Heart Sounds

lub: AV valves (into ventricle)

dub: closing of the semilunar valves (out of heart)

autorythmicity

heart capable of initiaing its own heartbeat

• SA (sinoatrial): roof of R atrium (sinus)

• AV (antrioventricular) node: floor of R atrium

• AV (antrioventricular bundles) = bundles of his

• right and left bundles @ superior septum

• purkinje fibers: located @ walls of vents

Coordinated sequence of heart chamber contractions

1. SA node generates impulse

2. atria contract (sys), ventricle relax (dia)

3. impulse goes to av node then ventricles (via conducting fibers)

4. ventricles contract (sys), while atria relaces (dia)

BBB

tight junctions bewtween capillary and endothelial cells

perivascular feet

Brainstem

autonomic and reflex centers

• mesencephalon (midbrain, maintain posture)

  • superior coliculus: visual reflexes

  • inferior colliculus: auditory reflexes

  • reticular formation: consciousness

• pons

• medulla oblongata

cranial nerves

trochlear: moves eye muscles

trigeminal: sensory and motor information of head and neck

abducens: moves eye muscles

glossopharyngeal: moves neck and tongue muscles

hypoglossal: neck muscles