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Flashcards in Exam II: General Concepts Deck (51):

3 Main Components of the Cardiovascular System

1. Heart
2. Blood
3. Arteries/Veins


Composition of Blood

1. Formed elements: heavier elements/cellular material including the RBC, WBC, and platelets
2. Plasma at the top, which is serum/liquid part outside the cells; contains water, Ab, proteins, electrolytes
Plasma is important because it is related to lymph


Location of the Heart

The apex of the heart ends at the 5th intercostal/nipple area
The heart sits on the diaphragm; the fibrous pericardium is fused to the diaphragm
The sternum is protecting the front, along with the ribs
The sternum is divided into 3 parts: manubrium is the top part, which is fused at the 2nd rib with the body of the sternum
The aortic arch and trachea bifurcation, pulmonary trunk that divide in the right and left = all behind the 2nd rib area/protected by the sacrum
At the 5th intercostal space= apex of the heart in a healthy normal heart
Right around rib 3 the top of the heart is there with the inferior and superior vena cava
The heart is about the size of your fist and between the 3rd and 5th ribs


Layers of the Heart

The fibrous parietal serous layer is the lining under pericardial sac
1. Epicardium: outside layer of the heart also known as the visceral serous layer
2. Fat is a good source of fuel right on the heart containing blood vessels + areolar connective tissue
3. Myocardium: middle layer; see lots of blood vessels because need good vascularization or have an MI
4. Endocardium: innermost layer; areolar connective tissue with endothelium (simple squamous epithelium in contact with blood)


Two Pumps of the Circulation

4 chambers of the heart divided into the pulmonary (send blood to lungs) and systemic circulation (send blood to the rest of the body)
Left side of heart has bigger ventricle because needs more pressure to pump the blood through the body
The aorta and big veins= systemic
Pulmonary artery= low O2 blood; pulmonary vein= high O2 blood from the heart


Great Vessels of the Heart

Bring in blood from the body:
Superior vena cava: bringing from the abdomen, thorax
Inferior vena cava: lower limbs and pelvis
Both go to the right atrium

Blood that is leaving:
Aortic arch sending blood to rest of the body
Pulmonary trunk that branch into right and left pulmonary artery


Chambers of the Heart

2 atria and 2 ventricles
Interventricular septum: separating the two ventricles
Interatrial septum: separating the two atria, which doesn’t close until birth


Valves of the Heart

Valves associated with fibrous skeleton and anchored to fibrous rings
Cartilage around the valves can calcify as we get older and not work as well
Valve: ensure unidirectional flow and prevent backflow
Pulmonary trunk is associated with the pulmonary valve
Aortic trunk associated with aortic valve
Mitral and bicuspid valves


Pathway Through the Heart

Go through inferior or superior vena cava into the right atrium, which will contract and will go through tricuspid/right atrioventricular valve, then to the right ventricle and tricuspid valve closes
Right ventricle contracts and goes up through the pulmonary semilunar valve to the pulmonary trunk into the right and left pulmonary arteries to the lungs to get gas exchange
Pulmonary veins come from lungs with fully O2 blood, to the left atrium, through the bicuspid valve/mitral/left atrioventricular valve, then the left ventricle and bicuspid valve closes to generate pressure and prevent backflow, and then the blood goes behind the pulmonary trunk area to the aortic semilunar valve leading to the aorta (ascending arch and descending arch) through the body and then the cycles starts again


Layers of the Blood Vessels

1. Tunica Intima: endothelium + basement membrane; innermost layer and in contact with the blood
2. Tunica Media: smooth muscle; middle layer
3. Tunica Adventitia: connective tissue; outermost layer and fuses with the vascular bundle
The artery and veins have the same layers, but different thickness


Comparison of Arteries vs. Veins

Elastic Artery: tunica media is largest with layer of elastin to allow for recoiling and generation of pressure to close cusps and prevent backflow; pulmonary trunk and aorta
Muscular Artery: renal, carotid; thick muscular wall with external and internal elastic lamina
Arteriole: fewer muscular thickness/smaller
Venules: fewer muscle cells than arteries
Medium sized vein: add VALVES to prevent backflow of the blood
Large veins: with valves still
Bigger blood vessels need their own blood supply = vasa vasorium
Arteries have a thicker tunica media


Innervation of the Heart

To maintain normal BP, we have specialized structures that relay back info to the brainstem that will in turn control blood supply and pressure
Aortic body: cells that are the associated with the cranial nerves/ vagus nerve X
Bifurcation of the carotid bodies: chemoreceptors that relay info about pressure and content of the blood via carotid sinus nerve to nerve IX



Varicose veins: the valves don’t function properly and don’t ensure unidirectional flow
Why don’t we have varicose veins within the deep muscle? We have another pump (skeletal muscle associated with the vein), and as we move/walk/run we are pumping/compressing it to help with blood flow
Musculoskeletal pump: doesn't work well with superficial veins, but works well for deep veins
Problem with deep veins: DVT from lack of movement causing blockage and embolism


3 Types of Capillaries

1. Continuous: not much leakage; blood brain barrier because don’t want blood mixing with tissue
2. Fenestration: leak only small molecules, mostly fluid; glomerulus because we want passage of fluids
3. Sinusoidal: missing half the walls with large fenestrations to allow bigger molecules to come out; liver, spleen (large pooling of blood)


Portal Circulation

Two in the Body:
1. Hepatic Portal System – involves drainage of the gastrointestinal tract (1st capillary bed) and liver (2nd)
2. Hypothalamic Hypophyseal Portal System – involves the delivery of hormones to the hypophysis

Arterioles to 1st capillary bed to vein to 2nd capillary bed, then into another vein then back to the heart

Artery to capillary to an artery to capillary to vein = glomerulus because efferent and afferent arteries



Have arteries that connect to each other; artery to artery connections and don’t have to come from the same spot
Blood vessels to small intestine

Anatomic: two arteries that go to tissues and DO NOT CONNECT
Functional: have a connection somewhere; if ligation in one of the arteries, the blood flow will still go to the tissues they both supply


Vascular Shunting

We do not always have the capillary beds fully used; need ability to close them because we wouldn’t have enough blood for the body otherwise
During digestion in the intestine the capillary beds are open completely, but once that ends they close down
Exercising: open vascular beds in muscles and lungs to get more O2 and blood flow
Shunting: do this via pre-capillary sphincter (have ability to close) so when the muscle constricts it closes off the passages to the capillaries


Pathway of Lymph Flow

Have cell products/debris, pathogens, fluids, etc. entering the lymphatic system via the lymphatic capillaries/plexus, which are filtered by lymph nodes containing lymphocytes and macrophages, exit the nodes via the hilum uni-directionally especially because the presence of valves, then goes into blood vessels
Blood vessels enter the heart circulation, capillary beds, then interstitial fluid back into the lymph capillaries


Lymphatic System

The lymphatic system (lymph nodes, spleen, etc.) returns excess tissue fluid back to the venous system. Lymph is rich in macromolecules, large proteins and particulate matter

Comprised of:
1. Lymph and channels
2. Lymphoid tissue

Functions to:
1. Transport lymph and cells
2. Absorption and transport of fat
3. Defense mechanisms


Lymphatic Vessels

Lymph vessels begin as blind ended pouches, and are highly permeable with a very low pressure
Lymph channels drain lipids from the GI tract

Lymph vessels are absent from:
1. Epidermis
2. Hair and nails
3. Cornea
4. Articular cartilage
5. CNS
6. Bone marrow


Regions of Lymph Node Clusters

Lymph drainage pathways are very important
Clusters of lymph nodes
Pattern that connects them together: many times associated with body openings especially to get rid of pathogens before they enter the body/cause infection

1. Deep nodes associated with aorta, celiac trunk, superior and inferior mesenteric arteries; sometimes called lumbar nodes because associated with the lumbar area
2. Axillary nodes: spread of breast cancer
3. Cervical nodes: neck/ internal jugular vein
4. Pericranial Ring: base of the head
5. Tracheal nodes: related to trachea and bronchii
6. Inguinal nodes: along inguinal ligament
7. Femoral nodes: along femoral vein


Lymphatic Anatomy

Lymphatic capillaries consist of a layer of endothelium with no basal lamina
Larger lymph vessels have a basal lamina, valves and three coats (intima, media and adventitia).

The movement of lymph depends on:
1. Filtration pressure
2. Contraction of muscles
3. Arterial pulsations
4. Respiratory movements
5. Smooth muscle in the vessels
6. OMM


Lymphatic Ducts

All lymph drains into two major lymph ducts:
1. Thoracic duct + cisterna chyli
2. Right lymphatic duct
cisterna chyli: lower end of the thoracic duct into which lymph from the intestinal trunk and two lumbar lymphatic trunks flow
As we pass lymph through the body, it moves either to the right or left subclavian areas
Right lymphatic duct to right subclavian will drain into the right subclavian trunk
Left face, arm, legs, etc. will drain into the jugulovenous angle: made of jugular and subclavian where thoracic duct returns lymph into the circulatory system


Nervous System Functional Divisions

Motor(efferent) and sensory (afferent) from CNS
GSE: Conscious control of motor/skeletal muscle; The general somatic efferents (GSEs) carry information away from the CNS and towards the skeletal muscles
GSA: conscious mind controls pain,cold, hot, smooth, rough = touch only; The general somatic afferents (GSAs) carry information from the periphery (outside environment) into the CNS (central nervous system)
GVE: not conscious control of smooth muscles, cardiac muscles, etc.
GVA: no conscious control of sense within the body (NOT eyes, ears, taste, etc.); senses stretch within the body like the bladder for example– don’t feel the stretch until reaches a certain point and then goes to the conscious mind


Sympathetic vs. Parasympathetic

Sympathetic: Fight or Flight; thoracolumbar
Parasympathetic: rest and digest; cranial sacral


Anatomy of a Nerve

Cell body/soma with organelles
Axon coming from soma and turns into synaptic knob/synapse with neurotransmitters
Coming into the cell body: dendrites

Multipolar: many dendrites coming in; all motor neurons
Bipolar: special sensory like back of the retina; one axon and one dendrite
Unipolar: all sensory neurons; one axon and with a short process


Spinal Cord

Brain stem passes through vertebral canal
Some areas are thicker and thinner
Thicker: in two places and called the cervical and lumbar enlargements
Cervical, thoracic (associated with ribs), lumbar, sacral, and coccygeal regions
In order to have neurons coming in and out to the limbs = thicker areas/enlargements



Spinal nerves that exit the spine and go out to the body, have a specific pattern to how they innervate the skin
Dermatomes: specific levels
Dermatomes have overlaps – gives redundancy
Say damage T2, dermatomes from T1 and T3 may not lose functionality



Spinal nerves pass through muscle first to get to skin
Group of muscles that a single spinal nerve root innervates



Isn’t used as much
Bones are innervated, especially the periosteum


Spinal Cord

Pairs of spinal nerves
Cervical: 8 pairs of nerves with 7 vertebral… C1 comes out above the C1 vertebra until C8 because they come out below
T1-12 so 12 pairs, L1-5 so 5 pairs, S1-5 so 5 pairs, and 1 coccygeal pair

Has cervical and lumbar enlargements so nerves can enter and exit to the rest of the body
Your spinal cord is the length of the vertebral canal at birth, but as we grow it doesn’t grow with us and ends at L1/L2, and in a cone called conus medularis and branches off into cauda eqina
Filum terminale: anchors the spinal cord; attaches sacrum and coccyx



Main Layers:
On the outermost part next to vertebral body itself is the dura mater (tough mother), can only cut it cannot tear it apart
Underneath dura mater, arachnoid mater because looks like spider web; directly on the spinal cord itself is the pia mater, which can form a little structure that will anchor = denticulate ligament

Associated with the layers:
Subarachnoid space between arachnoid space and pia mater = contains CSF
Epidural: located outside of the dura; subdural would be between the arachnoid and dura mater
Arachnoid and dura mater are directly on top of each other and don’t want them pushed apart


Spinal Nerve Anatomy

Gray matter is in the center with surrounding white matter (myelinated vs. unmyelinated)
Axon tracts are in the white/myelinated

Posterior roots: carrying the afferent nerves (sensory) through posterior rootlets to posterior root to posterior root ganglia (collection of cell bodies outside the CNS) unipolar cells are in sensory
Same pattern for Anterior roots except carrying the efferent/motor nerves


Neuron Pathway

Skin to afferent neurons to posterior root, connecting neuron, anterior root (efferent) to the muscle


Autonomic Nervous System

The job of the autonomic nervous system is to monitor and regulate function and blood flow to the viscera
The ANS is composed of GVE and GVA fibers
Viscera: think of anything that is a hollow tube; ureters, bladder, blood vessels, organs, etc.

G= General
V= Visceral
E/A = Efferent and Afferent


Afferent vs. Efferent

Afferent or sensory neurons receive information from the outside (sensory receptors) and sends them to other neurons so the body could produce a response

Efferent neurons or motor neurons receive information from other neurons and sends that information to effectors (muscles, glands), which produce a response


Visceral Efferent Pathway (GVE)

From the CNS, the GVE pathway utilize two neurons:
one in the CNS [brainstem or spinal cord]
one in the periphery [ganglia]

If sympathetic: first neuron is shorter, para the 2nd neuron is shorter
In both cases the first neuron originates either in the brain or spinal cord
The synapse always occurs in the periphery in a ganglia of PNS
GVE are two neurons pathways in SNS and PNS


Somatic vs. Visceral

Somatic Efferent Innervation: efferent to myelinated fiber to somatic effector (ex. Skeletal muscle)

Autonomic Efferent Innervation: efferent to myelinated pre-ganglionic, which synapses on the autonomic ganglia which goes into the unmyelinated post-ganglionic fiber to the visceral effector (ex. Cardiac muscle, smooth muscle, glands, etc.)


GVA and GVE Axons

The GVA fibers that course with the GVE’s are sensory and therefore must have a cell body in a sensory ganglia! Their axons pass through autonomic ganglia WITHOUT synapsing
Important: Autonomic fibers utilize pre-existing pathways to arrive at their target organ
GVA axons follow GVE axons, except in the ventral root


Division of the ANS

Parasympathetic/Craniosacral Division: cranial nerves: 3, 7, 9, and 10, and sacral region: S2-4; preganglionic neurons located in brainstem nuclei and S2-S4 regions of spinal cord
Sympathetic/Thoracolumbar Division: starts at T1 and goes to L1 or L2 depending on the person; preganglionic neurons located in lateral horns of T1-L2 regions of spinal cord
Both involved in homeostasis


Sympathetic Division

Sympathetics are involved in the fight or flight response
Sympathetic axons go everywhere…superficial and deep
Arise from ”thoracolumbar” spinal cord (T1-L2)


Intermediolateral Cell Column

The IMLs appear as small lateral horns of the H-shaped gray matter
Consists of the cell bodies of the presynaptic neurons of the sympathetic nervous system.
In the spinal cord at T1-L2 there is a special group of neurons located in the lateral horn of the gray matter collectively they run in a column=intermediolateral cell column (IML)


Structure of Sympathetics

Sympathetic Chain (Trunk): runs from the base of the skull to the tip of the coccyx
Sympathetic Chain Ganglia: "beads on a chain" and get many synapses here
White Rami: myelinated axons, only present at spinal cord levels T1 through L2
Gray Rami: contains unmyelinated axons, present at ALL 31 SPINAL CORD LEVELS

Posterior Root: contains somatic and visceral afferent/sensory fibers (comes from outside environment to the spinal cord/brain stem)
Anterior Root: contains somatic and visceral efferent/motor fibers (comes from spinal cord/brain stem to something inside the body)


Pathways of Sympathetics: Peripheral

Peripheral (Body Wall)

Pre-ganglionic originate between T1 and L2 IML, exit via anterior rootlets, to root, spinal nerve, white ramus, synapse, travel either up or down sympathetic chain and eventually exit via the gray ramus on the spinal nerve and distribute to the rest of the body; GVE

Postganglionic: has cell body in sympathetic chain ganglia, gray rami, dorsal and ventral rami
Posterior and Anterior rami at all 31 levels contain sympathetics


Pathways of Sympathetics: Organs Above the Diaphragm

Organs Above the Diaphragm

Preganglionic: IML pass through the ventral/anterior root, white ramus, synapse in the chain ganglia
Viscera above the diaphragm: T1-T4; GVE
Exits anterior to spinal root, sympathetic chain via white ramus travel up or down and synapse at the level, then form nerve that comes off the chain to the heart known as sympathetic cardiac nerves
Still a 2 chain thing

Postganglionic: has cell body in chain ganglia and leaves via a visceral nerve (e.g. cardiac nerve)

*Organs in the head, neck and thoracic cavity get sympathetic innervation directly from the sympathetic chain.


Pathways of Sympathetics: Organs Below the Diaphragm

Organs Below the Diaphragm

Preganglionic: derived from T5- L2 spinal cord levels; IML, pass through the ventral/anterior root, white ramus, courses in the sympathetic chain and leaves but DOES NOT SYNAPSE ON THE SYMPATHETIC CHAIN; then connects to form the splanchnic nerves (greater, lesser, least, lumbar, and sacral) which synapses with prevertebral ganglia and go through the blood vessels and travel to abdominal pelvic viscera

Postganglionic: has cell body in preaortic (prevertebral) ganglia and distribute to gut on blood vessels

*Organs in the abdominal-pelvic cavity get postganglionic sympathetics via preaortic ganglia


Parasympathetic Division

Parasympathetics are involved in the eat, rest and digest response
Parasympathetics only go to deep structures (except for the genitalia); parasympathetics DO NOT distribute to the skin
Arise from ”craniosacral” regions of the CNS

“Cranio”: cranial Nerves III, VII, IX and X

“Sacral”: there are parasympathetic fibers that arise from sacral regions of the spinal cord, specifically S2,3,4

**Follow the same general pattern as sympathetics**
**Ganglia are usually in the wall of the organ**
**Post-ganglionic axons are short**


Parasympathetic Division: Craniosacral Breakdown

GVE: originate at brainstem (3, 7, 9, and 10); 3, 7, 9= go to facial structures
Parasympathetic: secretomotor: lacrimal and stimulation secretion
Nerve 3 is eye constriction
Nerve 7: lacrimal gland and submandibular ganglion (tears and saliva)
9: parotid gland
10: big influence when travels through thorax and abdomen; provide parasympathetic to heart, abdomen, lungs, thoracic cavity, GI (entire until 2/3 the way through the colon)
Mid-gut to hind-gut transitions 2/3 through from lumbar to sacral
Pelvic organs= hind-gut and pelvic from S2, 3, 4
Most synapse on wall of organ then innervate


Sacral Pathway

Preganglionic cell bodies in a IML-like area situated in the sacral regions of the spinal cord
GVAs – arise from the same cord levels as the GVEs

It is motor, so exits anterior, AVOID THE SYMPATHETIC CHAIN, but branch off spinal nerve and synapse in the organ wall
Pelvic splanchnic nerves red arrow
All other splanchnic nerves are sympathetic; para is ONLY S2, 3, 4


Referred Pain

Visceral pain is dull and poorly localized [somatic pain is sharp and easily localized]

Damage to an organ typically does not “hurt” at the site of the organ. Rather the pain is “referred” to the body wall

GSAs enter the same spinal cord level as GVAs.

The brain and spinal cord is not “wired” to clearly localize pain information arising from the organs.


Referred Pain Map

Right Neck/Shoulder: liver, gallbladder, and duodenum due to irritation of diaphragm
Upper back/mid abdomen: stomach
Slightly under the right armpit: gallbladder
Right side: liver
Left Lumbar/groin: kidney and ureter
Slightly under the left armpit: spleen
Mid abdomen: duodenum and head of pancreas
Above the pelvis: appendix (radiating)
Mid pelvis: cecum and ascending colon
Right and Left Pelvis: sigmoid colon