John Clappin

Three Qualities

1. Monitors internal & external environments
2. Integrates sensory information
3. coordinates voluntary and involuntary responses of many other organ systems

Central Nervous System (CNS)

• Brain & Spinal Cord

Peripheral Nervous System (PNS) Central (Nerves and Ganglia)

• Sensory- Afferent
  • Exteroreceptors (Touch, Temp, Pressure, Smell, etc)
  • Proprioreceptors (Position and movement of skeletal muscles)
  • Interoreceptors – (monitor digestive, respiratory, cardiovascular, urinary and reproductive systems and taste)
  • Peripheral ganglions
• Processing – Interneuron, then on to the;
  • Somatic motor neurons – skeletal muscles
  • Visceral motor neurons – smooth muscle, glands, cardiac muscles, fat cells
• Motor – Efferent
  • Voluntary – Somatic
  • Involuntary – Autonomic
    • Sympathetic
    • Parasympathetic

Types of Nervous Tissues

• Neurons – basic unit of the nervous system (do not reproduce)
  • Dendrites – afferent – inbound
  • Cell Body
  • Axon Hillock (delta shaped as cell body becomes an axon)
  • Axon – Efferent
  • Axon Collaterals (off side of axons)(branches to different portions of muscles)
  • Axon Terminals
  • Synaptic End Bulbs (Neuromuscular terminal)
  • Synaptic Cleft
  • Dendrite of next neuron or effector organ
• Types of Neurons
  • Multipolar – most common in CNS
  • Unipolar – most sensory neurons of PNS
  • Bipolar – rare in special sense organs (sight smell, hearing)
• 

Saltatory Conduction ( impulses pause at breaks in myelin, draws in sodium)

Neuron

 

• Neuroglia – neuro glial cells – regulate the environment around the neurons providing support for neural tissue (do reproduce)
  • Ependymal Cells -secrete CSF
  • Astrocyte – largest and most numerous, secretes chemicals vital to maintain the blood-bran barrier which isolates CNS from general circulation.
  • Oligodendrocytes – secrete myelin to neural axons (myelin – makes them white, permits and controls movement of ions don the axon and does not go into surrounding tissues – insulation). Some cells are myelinated and some are unmyelinated. Multiple Sclerosis is a degenerative disease affecting myelin production.
  • Schwann Cell – PNS cell similar to Oligodendrocytes  – covers every axon in the PNS
  • Everything white is myelin. Everything gray is accumulated cells.

Neural Communication

• Chemical Neurotransmitters – information transfer at synaptic terminals occur via the release of neurotransmitters.
  • Norepinephrin (primary sympathetic neurotransmitter)
  • ACh (primary parasympathetic neurotransmitter) (AChE breaks it down in the cleft to allow the receptors to open for the next transmission)
  • Dopamine
  • GABA
  • Serotonin
  • Melatonin
  • etc,

Synaptic Cleft

Nerves

Cell bodies are frequently grouped together;

• In CNS – called Nuclei, Nucleus
• Outside CNS – called Ganglion,Ganglia
• Fascicle – groups of neurons bundled together, surrounded by connective tissue. Nerves contains multiple bundles of fascicles(outside CNS, inside CNS called Tracts)

Anatomy of the Spinal Cord

• Starts at Foramen Magnum – runs down to L1
• Cervical region is thicker, called cervical enlargement – same at bottom, called lumbar enlargement
• Conus medullaris – cone like end of SC
• Cuada Equina – after spinal cord ends – threadlike (spinal taps, epidurals, etc. happen here)
• 32 spinal nerves – beneath each of the vertebrae
• Nerves from spinal cord contain both efferent and afferent neurons – split just before spinal cord – dorsal roots(sensory – with dorsal ganglia) and ventral roots (purely motor – cell bodies in are in the spinal cord)
• Grey Horns (anterior and posterior)
• Anterior and Posterior White Columns (contain tracts) (posterior – ascending tracts, anterior – descending tracts)
• Central canal – contains CSF
• Meninges
  • Pia Mater – first protective layer of spinal cord (very tightly wrapped)
  • Subarachnoid space – between pia mater and arachnoid layer – filled with CSF
  • Arachnoid layer – looks like a spider’s web
  • Spinal dura mater
• 
• 

The Brain

• cerebral cortex -is a structure within the brain that plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness.
• cerebrum
  • divided into cerebral hemispheres
• diencephelon
  • Hollow, largest portion is the thalamus – which contains relay and processing for sensory information. Hypothalamus is connected to the pituitary gland. The hypothalamus contains centers involved with emotions,autonomic function and hormone production. The pituitary gland is the prmary link between the nervous and endocrine systems.
• Brain Stem (responsible for all vegetative function and almost all cranial nerves originate here)
  • midbrain – process visual and auditory information and generate involuntary responses. also has regions that help maintain consciousness.
  • pons – or bridge, connects cerebellum to brain stem. also contains tracts involved in visceral and somatic control. Also connected to the medulla oblongata
  • medulla oblongata – segment of brain attached to the spinal cord. relays information to the thalamus and other parts. regulates lots of autonomic function including heart rate,BP, respiration and digestion.
• cerebellum – adjust voluntary and involuntary motor activities based on sensory information and stored memory of previous movements.
• Ventricles – 1st through 4th – chambers filled with CSF
•  

The Peripheral Nervous System (PNS)

• 12 Pairs of Cranial Nerves (future post – see table 8-2 on page 297)
• Nerve Plexus – PNS network of intersecting nerves
  • Cervical plexus – serves the head, neck and shoulders
  • Brachial plexus – serves the chest, shoulders, arms and hands
  • Lumbar plexus – serves the back, abdomen, groin, thighs, knees, and calves
  • Sacral plexus – serves the pelvis, buttocks, genitals, thighs, calves, and feet
  • Solar plexus – serves internal organs
  • Coccygeal plexus – Same as Solar Plexus

    Since the Lumbar and Sacral plexus are interconnected, they are sometimes referred to as the Lumbosacral plexus. The nerves that serve the chest are the only ones that do not originate from a plexus

• Dermatomes
  • 

John Clappin

3/8/09

Cardiovascular System

Heart

• Two Sided pump – each side contracts together (atria and ventricles)
  • Systemic circuit
  • Pulmonary Circuit
• Landmarks:
  • Angle of Louis (or Sternal Angle – formed at bottom of Manubrium where meets the sternum) – 2^nd rib to the left base of heart, major vessels
  • 6^th Rib – Apex of heart in 5^th intercostal space – left midclavicular line
  • Right border of sternum
• Heart Sounds – S1 – when AV valves shut (5^th intercostal space –tricuspid valve right sternal border, mitral valve(bicuspid)– 5^th intercostal space left midclavicular line), S2 when semilunar valves shut (2^nd intercostal space right and left)(vibrations of blood not actual valve sounds)
  • Abnormal Sounds –
    • S3 is a rare extra heart sound that occurs soon after the normal two “lub-dub” heart sounds (S₁ and S₂)- sign of Left Sided CHF or Mitral regurgitation – (sounds like Kentucky?)
    • S4, atrial kick (Tennessee?) S₄ is a rare extra heart sound that occurs immediately before the normal two “lub-dub” heart sounds (S₁ and S₂). It occurs just after atrial contraction and immediately before the systolic S₁. S₄ is caused by the atria contracting forcefully in an effort to overcome an abnormally stiff or hypertrophic ventricle.
• Blood flow
  • Vena Cava to R atrium
  • Through R AV Valve (tricuspid) into R Ventricle
  • Through pulmonary (pulmonic) semilunar valve to pulmonary arteries and lungs (pulmonary circuit)
  • Back from lungs through pulmonary veins into left atrium
  • Through L AV valve (bicuspid or mitral) into left ventricle
  • Through aortic semilunar valve out to aorta and systemic circuit
  • Structures of valves
    • Chordae tendinea – tendons (attached to ventricular wall by papillary muscles) that attach to the cusps of the AV valves, during contraction these tendons pull the cusps shut, thereby preventing backflow or regurgitation (regurgitation will cause a heart murmur)
    • Coronary sulcus – separates atria from ventricles
    • Coronary sinus – is a collection of veins joined together to form a large vessel that collects blood from the myocardium of the heart.
    • The trabeculae carneae are rounded or irregular muscular columns which project from the whole of the inner surface of the ventricle, the purpose of the trabeculae carnae is most likely to prevent suction that would occur with a flat surfaced membrane and thus impair the heart’s ability to pump efficiently. The trabeculae carnae also serve a similar function to papillary muscles in that their contraction pulls on the chordae tendinae, preventing inversion of the mitral (bicuspid) and tricuspid valves. This prevents backflow of blood from the ventricles into the atriums.

Anatomy of thoracic cavity and Heart

• Left pleural cavity, right pleural cavity, and mediastinum (each made of a serous membrane)
  • Endocardium –inner layer of heart – smooth muscle
  • Myocardium – middle muscular layer
  • Epicardium aka visceral pericardium – outer layer
  • Pericardium – Cavity that surrounds the heart, visceral pericardium (inside) and parietal pericardium (surrounded by dense fibrous layer -attached to chest wall) filled with pericardial fluid – purpose is to protect heart and provides a degree of lubrication for heart to beat. Normally contains about 30 mL of serous fluid

Becks Triad – The result is the triad of 1. Low arterial blood pressure (reducing stroke volume and CO) 2. Increased central venous pressure (evidenced by JVD), and; 3. Distant heart sounds. Narrowing pulse pressure may also be observed.

• Cardiac Tamponade – sudden due to trauma
• Pericarditis – slower, due to infection

Electrical conductivity of the heart (basically – to be discussed in further detail in later lectures) Monitored by using an EKG Machine

• Starts in SA node
  (Pacemaker at 60-100 beats per minute)
• Slows in AV node so AV valve can effectively allow the blood to pass (100 msec delay) atrial contraction begins
• AV junction (includes AV node, surrounding tissue, and Bundle of His)
• AV Bundle (Bundle of His)(Pacemaker at 40-60 beat per minute)-then to Bundle Branches (Left and Right)
• Purkinje Fibers – distributes throughout the ventricular myocardium – ventricular contraction begins (Pacemaker at 20-40 beat per minute)

(See Palpitations)

Some random points

• Antiarrthymic drugs – act specifically on cell membranes of ectopic sites and blocks sodium from entering cell –
• Vasovagal response – stimulating the vagus nerve will cause overstimulation of parasympathetic nervous system, causing bradycardia – Valsalva
  maneuver

Cardiac Output (CO) Stroke volume x pulse rate

2/2/09

Functions of the respiratory system

1. Exchange of gases
2. Excretory function (volatile substances – alcohol, garlic, acetone, etc)
3. Acid Base Balance

Metabolic and aerobic metabolism

Respiratory Physiology

1. Ventilation
   1. Hyper/Hypo refers to depth of ventilation and leads to hypo/hyper carbia
   2. Eupnea – normal breathing
   3. Tachypnea
   4. Braydpnea
   5. Apnea
   6. Dyspnea
2. External Respiration – alveolar capillary membrane (also have bearing on acid/base levels due to transport of co2)
3. Internal Respiration – cellular respiration (also have bearing on acid/base levels due to transport of co2)
4. Transportation of Gases – O2 transported on hemoglobin, (hemoglobin is directly affected by temperature, in cold it picks up O2 but does not release it easily in the tissues – red cheeks because blood is cold O2 stays in the vessels) alkalosis – o2 not given up by Hgb, acidosis- o2 given up by Hgb much faster
5. Regulation –

Physics of ventilation

1. Boyle’s Law – describes how air moves in and out of lungs
   
2. Dalton’s Law of Partial Pressure – distribution of gas
   
3. Henry’s law of Solubility of gases – describes how gases dissolve in water
   

To be continued….

2/2/09

More on capillaries…lymph, etc

Blood pressure would force blood to flow out of capillaries into the interstitial spaces both on arteriole side and venous sides. This couldn’t work obviously. In the plasma you have dissolved proteins (albumins) and electrolytes; they are large molecules and can’t leave the capillaries under normal conditions. Therefore the interstitial spaces are hypotonic with respect to the plasma. Osmosis draws the fluid back into the bloodstream. The movement across the membrane is via osmotic pressure; the pressure caused by the albumin is oncotic pressure (40mm hydrostatic pressure outside – 25mm oncotic pressure inside the arteriole – net 15mm) On the venous side it is net -10mm and pulls fluid back in. Not equal, more pushing out of arteriole side than being pulled into venous side. Excess hydrostatic pressure / excess water is picked up by lymphatic capillaries and returned to circulation by lymphatic system. Lymph has the same composition as plasma except for the proteins. (the result of low oncotic pressure can be edema – excess fluid buildup in the tissues.)

Lymph nodes, Spleen & Thymus, filter returning lymph to remove disease and infection.

Some complications:

If hydrostatic pressure increases on arteriole side, even a little on venous side too. Now you have no movement on venous side because oncotic and hydrostatic pressure are equal. Will result in edema or Pulmonary Edema in the lungs.

Blunt Trauma- slashes and cuts cell membranes, capillaries, etc. as a result they bleed into the tissues (hematoma) when you break these capillaries the albumins leak into interstitial spaces. Now they draw fluids out of capillaries – increases swelling, (enough will cause compartment syndrome)

Anaphylaxis – one of cells in connective tissues are mast cells don’t do anything unless they are stimulated. Stimulated in injury to the tissue and release histamine. Histamines act directly on the capillary and it makes the capillary more porous to albumins. Now that there are more albumins in the interstitial space you end up with increased fluid in the interstitial spaces, redness caused by leaking RBCs.(ankle, lungs, etc .anywhere there is an injury) In anaphylaxis there is an overstimulation/over production of histamine in every cell in the body due to an allergy, causing the entire body to swell (alveoli, larynx, skin, etc)

Burns – 2^nd degree have blisters. Blisters contain fluid, interstitial fluid. When you have a partial thickness burn, when you burn the dermis you cause mast cells to secrete, causing fluid to accumulate, large burns = lots of broken capillaries = lots of histamine released causing lots of fluid loss.

Dehydration – not taking in enough fluids, results in decreased hydrostatic pressure, thereby pulling fluid from interstitial spaces to maintain homeostasis. Skin can become taut and tented as a result. (Compensatory mechanism to maintain circulation in the core areas of body)

Hypovolemia – much faster vs dehydration. Rapid loss of fluid will not have time for decrease in the hydrostatic pressure enough to make up fluid loss like in dehydration.

CHF – Right side – pedal edema, left side, pulmonary edema –(cardiogenic shock, failure of both sides – no edema)(Furosemide given as a diuretic and acts as a vasodilator as well, maximize storage of blood, lessens return to heart, same thing for NTG)

Cardiac asthma, fluid leaks into bronchioles and alveoli causing lumens to become narrow, causing wheezing – same sound as asthma but different cause (fluid vs bronchoconstriction).

Colloid fluids will draw fluids from interstitial spaces; will help make up blood volume, will not diffuse easily like crystalloid solution which would NOT stay in the circulatory system for very long. 3:1

1/5/09 – NEEDS WORK!

Plasma –% of blood

• Formed elements `
• Albumins?
• RBC carry o2 via their hemoglobin
• 1 cubit mm contain 3 million RBC
• Thrombocytes – platelets –
• WBC-
  • Neutrophils – active phagocytes , first to arrive at scene of injury (50-70% of wbc)
  • Lymphoctes – (20-30% of wbc)
  • Monocytes

Plasma -92% water, plasma proteins are biggest contribs to osmosis

Lymph = interstitial fluid

To be continued…

1/5/2009

Cell membranes and other goodies

Phospholipid bilayer

• Hydrophilic – inside
• Hydrophobic – towards outside

• Solubility – Lipid soluble will pass through easily
• Size of the particle
  • Proteins or glucose – larger
  • Ions and electrolytes- smaller

(Insulin permits glucose to cross the membrane)

Passive transport

• Aqueous environment
• Solution – liquid + electrolytes or ions (solvent + solute)
• Suspension – liquid + non electrical (proteins)

Diffusion

• Simple diffusion will allow solutes to cross membrane if conditions are met
  • Sodium & potassium ‘leak’ through (sodium potassium exchange pump recaptures the ‘escaped’ ions) (60-100 times per min)
    • PVC – sodium leaking
• Filtration – substances moving across semi permeable membrane under influences of hydrostatic pressure
• Osmosis

12/3/08

Fluids display such properties as:

• Not resisting deformation, or resisting it only lightly (viscosity), and
• The ability to flow (also described as the ability to take on the shape of the container).
• Flow from high pressure to low pressure

Types of fluid

• Gases
• Liquids

Pressure

• Force – push or pull (The action of a force against some obstacle or opposing force)
• Force over a specific area
  

Hemodynamics (the study of blood flow or the circulation)

Structure

• Internal – Tunica Interna – (tunica intima) simple squamus epithelia, endothelium, smooth. (atherosclerosis causes deposits that interrupts smoothness of vessel wall)
• 2^nd layer – Tunica Media – smooth muscle tissue –elastic tissues MUCH THICKER IN ARTERIES THAN VEINS
• Outer – Tunica externa -(tunica adventitia) Smooth muscle tissue , elastic fibers, collagen fibers (aneurysm – when blood flows between 2^nd and outer layer) (Aortic aneurism – sudden sharp abdominal pain, hx of HTN, absent dorsalis pedis pulse)
• Veins- Little muscle, very elastic – also called capacitance vessels
• Arteries (Resistance vessels)(BP measures the resistance against these arteries)
  • Elastic artery –elastic layer in tunica interna (found in
    aorta, brachial, femoral, – largest arteries) Expands as pulse wave passes through –pushing it along.
  • Muscular artery –Larger amount of muscle, smaller arteries/
  • Arterioles –
• Capillaries – one squamus cell thick, one RBC through at a time)(Where artery meets vein)have gaps in walls, mediators between tissues and vascular system
  • Precapillary sphincters – control flow to particular capillaries/tissues
• See graphic on page 469 for comparison of different vessel sizes
• 64% of blood found in veins
• 7% Heart

• Blood Pressure – force of blood against walls of blood vessels
  • Systolic – Pressure during a pulse wave – heart contracts and blood goes out as a pulse wave, greater volume and higher pressure.
  • Diastolic – Pressure that remains in the vessel when heart is at rest
• Systemic BPs – Aorta /Muscular artery – 120/80, small arteries 100/80mm, artery side arteriole 40mm, capillaries 20mm, venous side 15mm, right atrium 0mm
  • Cardiac output (CO)– stroke volume x Heart rate (stroke volume -amount of blood ejected with each pulse wave- avg 70cc)
    (lower CO causes decrease BP)
  • Total peripheral resistance – (TPR) is the sum of the resistance of all peripheral vasculature in the systemic circulation.
    • arteriosclerosis – hardening of arteries – increase TPR – heart pumps harder, cardiomegaly, cardiac hypertrophy)
    • anaphylaxis, neurogenic shock, cardiogenic shock, reduce TPR thereby reducing BP – (reverse by giving epi causing vasoconstriction)
    • increase TPR – Increase BP
    • TPR regulation – vasoconstriction and vasodilation

Venous BP is 15mm – how does it move up the body – from distal to proximal?

• Voluntary muscular contractions – (walking, rolling at night, movement while sitting , etc)
• Valves – open and close during muscle contraction (one way valves) (varicose veins – caused by damaged valves, loss of strength causing bulge, can become static and then CLOT or thrombophlebitis)
• Intrathoracic pressure chambers – affects right atrium

Also see Baroreceptors

From wiki….

In cardiovascular physiology, the baroreflex or baroreceptor reflex is one of the body’s homeostatic mechanisms for maintaining blood pressure. It provides a negative feedback loop in which an elevated blood pressure reflexively causes blood pressure to decrease; similarly, decreased blood pressure depresses the baroreflex, causing blood pressure to rise.

The system relies on specialized neurons (baroreceptors) in the aortic arch, carotid sinuses, and elsewhere to monitor changes in blood pressure and relay them to the brainstem. Subsequent changes in blood pressure are mediated by the autonomic nervous system.

Lecture on 11/24/08

Tissues

Muscle tissue

• Skeletal –striated – needs a nerve impulse to contract (sodium injected)
• Cardiac – also striated but different – striations are networked from fiber to fiber –intercalated discs
  - permit electrical activity to be conducted, cell membrane designed to make sodium spontaneously – cells that leak sodium the fastest are the pacemakers. SA node fires and set off for the entire heart (main pacemaker)
• Smooth – AKA Visceral muscle, no striations – lining of all tubes internal to body. Autonomic Nervous system (both para and sympathetic) controls contractions of smooth muscle

(Sodium need for every muscle movement – sodium depleted = abnormal muscle function, first leading to cramps, etc)

Neural tissue

• Neurons – carry chemical and electrical impulses
  
• Neuroglia – supporting cells

Epithelial Tissue cont.

• Glands –
  
  • Exocrine
  • Endocrine
  • Goblet cells (unicellular)
  • Secretory sheets (multicellular) (lines the stomach and protects it from its own acids)
  • Modes of secretion
    
    • Merocrine – released from secretory vesicles by exocytosis (cell stays intact) (mixed with water = mucus) (saliva, perspiration, milk)
      
    • Apocrine – loss of cytoplasm and secretory product (milk)
      
    • Holocrine – entire cell becomes packed with secretions and then bursts and dies (sebaceous glands) (skin oils)
      

Types..

Mucous membrane

Connective Tissue – have;

• Specialized cells
• Protein fibers
• Fluid known as ground substance
  
• Never exposed to the outside environment
  
• Many are very vascular
  
• Extra cellular protein fibers and ground substance form the matrix that surrounds the cell
  

Functions:

• Support and protection
• Transportation of materials
• Storage of energy resources (fats, adipose tissue)
• Defense of the body

Types

• Connective tissue proper (contains many types off cells and proteins surrounded by a syrupy matrix, eg fatty tissue, tendons and ligaments) fibroblasts, macrophages, fat cells, mast cells. Fibers- collagen, elastic fibers, reticular fibers – loose or dense –
  • Loose forms the layer that separates the skin from underlying muscles ad provides padding, etc. – adipose tissue,
  • Dense – mostly collagen
    
    • Dense regular – collagen fibers parallel to each other, packed tightly (tendons – muscle to bone, ligaments – bone to bone)
    • Dense irregular – interwoven – (skin)
• Fluid connective tissues – (distinctive population cells surrounded by watery matrix – eg. Blood and lymph)
• Supporting connective tissues -
  

Terms

Synovial fluid, synovial membrane

11/16/08 (notes from lecture on 11/23 added in red)

 Groups of like cells combine to form tissues. 4 basic types exist

• Epithelial
• Connective –most common, consists of blood, bindings,
• Muscle – main component – microfilaments – all organs have
• Neural – respond to stimuli

Epithelial, include glands and epithelia, important characteristics are

• Closely bound together
• A free surface exposed to environment or internal passageway
• Attachment to underlying connective tissue by basement tissue – attached with protein fibers
• Absence of blood vessels.
• Continually replaced and regenerated – using stem cells

Epithelia cover the skin as well as line the internal passageways that communicate with outside and protect the internal environment from the outside. They also are used in serous lining of internal cavities, and prevent friction, and restrict communication between blood and tissue fluids

Four essential functions

• Physical protection
• Control permeability
• Provide sensation
• Provide specialized secretions , also called gland cells
  • Exocrine – to the outside, sweat, milk
  • Endocrine – inside, hormones

Types of epithelia

• Simple – single layer, thin, fragile, only found internally in protected areas, found in places where secretion or absorption occurs like lungs, lining of GI tract, etc.
• Stratified – multiple layers`- greater degree of protection. Skin, mouth, anus,

Cell shape

• Squamus, flat
• Cuboidal, box like
• Columnar, taller and more slender

Where found

• Simple squamus, protected regions like kidneys, lungs, lining of blood vessels, inner surface of the heart
• Simple cuboidal- limited protection, secrete enzymes and buffers in the pancreas and salivary glands
• Simple columnar – some protection, also is areas of secretion or absorption, line stomach, GI tract and many excretory ducts
• Pseudostratified – looks layered due to varying heights but really not, usually posses cilia and line most of the nasal cavity, trachea , bronchi and male reproductive tract
• Transitional – withstands lot of stretching. Lines ureters and urinary bladder where large changes in volume occur
• Stratified squamus –can withstand severe stress. Skin, mouth, tongue, esophagus…
• (Very cool when viewed using an ultrasound machine)

To be continued……