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PHM145 Anatomy and Histology > Test 2 > Flashcards

Test 2 Flashcards

1
Q

Functions of the ANS

A

-Functionally maintaining homeostasis
-Regulates body temperature via control of sweat glands and vascular smooth muscle
-Regulates the activity of body systems
+CV, respiratory, digestive, excretory, reproductive system
-Monitors and adjusts body fluids, fine-tuning concentrations of electrolytes, nutrients, and dissolved gases

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2
Q

Autonomic vs. Somatic Nervous Systems

A

SOMATIC
-Neurons in the CNS synapse directly onto effectors
-Innervates skeletal muscle in the body wall and limbs, as well as overlying skin
Brain stem—somatic motor neuron—>skeletal muscle

AUTONOMIC
-CNS controls effects via a two neuron chain
-Innervates visceral organs, since there is no skeletal muscle there
Brain stem—preganglionic neuron—>Autonomic ganglia—postganglionic neuron—>smooth or cardiac muscle/glands

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3
Q

Parasympathetic vs. Sympathetic Nervous Systems: Preganglionic Neuronal Cell Bodies

A

CNS
PARASYMPATHETIC
-CRANIOSACRAL: brainstem cranial nerve nuclei and spinal cord (S2-S4)

SYMPATHETIC
-THORACOLUMBAR: Spinal cord levels (T1-L2)

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4
Q

Parasympathetic vs. Sympathetic Nervous Systems: Postganglionic Neuronal Cell Bodies

A

PNS
PARASYMPATHETIC
-Ganglia are located IN OR NEAR TARGET ORGAN (intramural)

SYMPATHETIC
-Ganglia are located near the spinal cord in either the PAIRED SYMPATHETIC CHAIN GANGLIA or UNPAIRED PREAORTIC GANGLIA

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5
Q

Parasympathetic vs. Sympathetic Nervous Systems: Preganglionic Neurotransmitters

A

ACh is released and used on nAChRs on the postganlionic neuron

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6
Q

Parasympathetic vs. Sympathetic Nervous Systems: Postganglionic Neurotransmitters

A

PARASYMPATHETIC
-Release ACh and act on MUSCARINIC AChRs

SYMPATHETIC

  • Most release NOREPINEPHRINE
  • Exceptions
    1. Adrenal Medulla releases 80% epinephrine/20% NE
    2. Sweat glands release ACh and act on mAChRs
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7
Q

Organization of the Spinal Grey Matter

A

-DEEP: Grey matter forms a continuous column extending the length of the cord
-ALL LEVELS: Grey matter forms a butterfly in cross section, divided into
+DORSAL HORNS - Sensory; receives input via spinal nerves and dorsal roots
+VENTRAL HORNS - Somatic motor; conducts output via ventral roots and spinal nerves
-CERTAIN LEVELS: INTERMEDIOLATERAL CELL COLUMN contains autonomic preganglionic motor neurons and conducts output via ventral roots and ensuing nerves

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8
Q

Sympathetic Division

A

TARGETS

  • Smooth muscle of limbs and body wall
  • Viscera of head and thorax
  • Viscera of abdomen and pelvis

-Preganglionic neurons located in the lateral grey horns (T1-L2)
-Axons travel via ventral roots, spinal nerves and synapse onto the postganglionic neurons located in the sympathetic ganglia near the vertebral column, either:
+in bilaterally paired SYMPATHETIC CHAIN GANGLIA
+in unpaired PREVERTEBRAL GANGLIA
-Postganglionic axons innervate the target organ

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9
Q

Sympathetic Innervations: Body Wall and Limbs

A

-Body wall and limbs are innervated by postganglionic sympathetic neurons located in the paravertebral or sympathetic chain ganglia
-Target organs are smooth muscle of erector pili, blood vessels, and glands of all dermatomes
-Preganglionic sympathetic fibres can ascend or descend within the sympathetic chain ganglia before synapsing
+Chain exists so we can get to the other dermatomes that are controlled by spinal nerves not in T1-L2

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10
Q

Sympathetic Innervations: Thoracic Viscera and Face

A
  • Innervated by postganglionic sympathetic nerves in the paravertebral or sympathetic chain ganglia
  • THORAX: Axons of postganglionic nerves form SPLANCHNIC nerves (cardiac, pulmonary, esophogeal splanchnic nerves), which contribute to AUTONOMIC PLEXI (cardiac, pulmonary, esophogeal plexi) that innervate targets in the thorax
  • FACE: Axons of postganglionic nerves for AUTONOMIC PLEXI, which hitch a ride with arteries to reach their targets; plexi named after the artery it travels with
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11
Q

Sympathetic Innervations: Abdominopelvic Viscera

A

-Innervated by postganglionic sympathetic neurons located in the PREVERTEBRAL ganglia (celia, superior and inferior mesenteric ganglia)
-Axons of the postganglionic neurons contribute to AUTONOMIC PLEXI, which hitch a ride with the arteries to reach their target organs
+Named by the blood vessel (celiac, inferior and superior mesenteric plexi)

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12
Q

Adrenal Medulla

A
  • One of the portions of the mixed glands that sits on top of the kidney
  • Modified sympathetic ganglion
  • Innervated by preganglionic sympathetic neurons of the lateral grey horns
  • Postganglionic neurons of the adrenal medulla release epinephrine and norepinephrine, which is picked up by blood vessels for systemic distribution
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13
Q

Parasympathetic Nervous System Division

A

-Preganglionic neuronal cell bodies located in the brainstem cranial nerves and axons travel via the cranial nerves
-Intermediolateral cell column (S2-S4) where autonomic preganglionic motor neurons are located; conducts output via ventral roots and ensuing nerves
-Ganglia are located near the effector organs
-Short postganglionic fibres innervate the cells of the effector organs
-CRANIAL NERVES
+III, VII, IX innervate viscera of the FACE
+X (Vagus nerve) innervates viscera of the THORAX and most of ABDOMEN
+Pelvic splanchnic nerves innervate the viscera of the DISTAL ABDOMEN AND PELVIS

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14
Q

Autonomic Plexi

A
  • Overlap of the sympathetic and parasympathetic nervous systems
  • Plexus is a network of nerves

THORAX named by target

  1. Cardiac plexus
  2. Pulmonary plexus
  3. Esophogeal plexus

DIGESTIVE TRACT named by blood supply

  1. Celiac plexus
  2. Superior mesenteric plexus
  3. Inferior mesenteric plexus

OTHER

  1. Hypogastric plexus
  2. Pelvic plexus
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15
Q

Autonomic Afferents: Homeostatic Input

A
  • Afferents from an organ retrace the path taken by the efferents, so if you know the motor output, you know the sensory input
  • Afferents carrying homeostatic sensory information generally travel with PARASYMPATHETIC EFFERENTS, which is generally the VAGUS NERVE (with the exception of the distal digestive tract and pelvis)
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16
Q

Autonomic Afferents: Visceral Pain

A

-Viscera are insensitive to cutting, burning and freezing
-Visceral pain is caused by:
1. Ischemia - lack of blood flow/oxygen
2. Distension
3. Inflammation
4. Blood
5. Etc.
-Visceral pain usually travels with the SYMPATHETIC EFFERENTS
-In the spinal cord, overlap with afferents from the T1-T5 dermatomes gives rise to the referral of cardiac pain to these dermatomes (ie. chest, armpit, medial arm) –> REFERRED PAIN
+Pain due to visceral damage is perceived as coming from the body wall because the dorsal horn is sensory and also receives from the heart afferents so the cells are not sure where the signal is coming from and thus interprets it as coming from the body wall

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17
Q

Cardiovascular System

A
  • Closed system
  • Heart is a double pump
  • RIGHT moves blood through PULMONARY circulation
  • LEFT moves blood through SYSTEMIC circulation
  • ARTERIES carry blood AWAY from heart
  • VEINS carry blood TOWARD heart
  • Gas exchange occurs across the walls of CAPILLARIES
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18
Q

Structure of Large Blood Vessels

A
  • Walls of arteries and veins consist of 3 distinct layers, innermost to outermost
    1. Tunica intima
    2. Tunica media
    3. Tunica externa/adventitia
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19
Q

Tunica Intima

A

-Endothelium (SIMPLE SQUAMOUS) lines all blood vessels and heart chambers
+Selectively permeable barrier (simple diffusion, active transport, pinocytosis, receptor-mediated endocytosis)
+NONTHROMBOGENIC discourages clot formation - smooth, nonturbulent, secretion of anticoagulants (thrombomodulin), and antithromogenic agents (Tissue Plasminogen Antigen)
+Can modulate vascular resistance, and therefore blood flow, through release of NO, and the action of membrane-bound enzymes
+Regulation of immune responses by expression of leukocyte adhesion molecules which control leukocyte adhesion and transmigration
-Subendothelial fibroelastic CT
-In some vessels, the INTERNAL ELASTIC LAMINA

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20
Q

Tunica Media

A
  • Concentric layers of smooth muscle cells spray around vessel
  • VASOCONSTRICTION increases vascular resistance; NO triggers relaxation of smooth muscle cells
  • VASODILATION decreases vascular resistance
  • Sympathetic input controls vessel diameter
  • In some arteries, alternate layers of ELASTIN, a fenestrated elastic layer
  • In some vessels, the EXTERNAL ELASTIC LAMINA
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21
Q

Tunica Externa/Adventitia

A
  • CT sheath connecting blood vessel to surrounding structures
  • In larger vessels, contains VASA VASORA (own blood supply)
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22
Q

Structure of Arteries: Elastic Arteries

A

-Largest arteries, closest to the heart
-Includes aorta and main branches (brachiocephalic trunk, common carotids, subclavians, common iliac arteries)
-Tunica media contains abundant elastin in the form of fenestrated sheets
+Modulates changes in BP during cardiac cycle
+Propels blood between contractions of heart
+Internal and external elastic laminae (in tunica intimate and media, respextively) due to layers of elastin
-Left ventricle contraction fucks with aorta all day long
+Cistalae: Passively stretched the peak of systolic blood to be not as high
+Diastalae: Drop in BP, aorta bounces back and helps to propel blood forward through the vascular tree

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23
Q

Structure of Arteries: Muscular Arteries

A

-Intermediate in size
-Distribute blood to body organs
-Includes renal arteries, gastric arteries, arteries supplying skeletal muscles
-Tunica media contains higher proportion of smooth muscle fibers (relative to elastin)
+Most modifiable because the smooth muscle can relax or constrict (increase vascular resistance) so the body can supply blood to specific organs as needed
-Internal and external elastic laminae prominent
-Regulates blood flow to organs according to tissue requirements

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24
Q

Structure of Arteries: Small Arteries

A
  • 3-6 layers of smooth muscle

- Internal elastic lamina present, which is modulatable due to smooth muscle)

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25
Q

Structure of Arteries: Arterioles

A
  • 1-2 layers of smooth muscle
  • No elastic laminae
  • Thin, ill-defined tunica externa
  • Controls blood flow into capillary beds through changes in vascular resistance
  • Vascular tone controlled by SYMPATHETIC NS, local conditions, and hormones
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26
Q

Capillaries

A
  • Consist of endothelium and basement membrane rolled into a tube
  • May be smaller in diameter than RBC
  • Thin walls allow rapid exchange of fluids, gases, metabolites, and waste products between body compartments
  • PERICYTES are cells associated with capillaries that may contribute to BV remodeling and wound healing
  • Classified according to PERMEABILITY
    1. Continuous capillaries
    2. Fenestrated capillaries
    3. Sinusoids
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27
Q

Continuous Capillaries

A

-Least permeable
-Most common
+Found in the brain, lungs and muscle
-Complete endothelial lining with tight junctions and desmosomes
-TRANSCYTOSIS - process of ferrying cargo from one side to the other

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28
Q

Fenestrated Capillaries

A
  • Found in: endocrine tissue, small intestine, choroid plexus, kidney
  • Pores in endothelial cell walls permit rapid exchange of peptides and small proteins
  • Fenestrae may form when pinocytotic vesicles span the cytoplasm of the endothelial cell and open on both surfaces
  • Number and size of fenestrae varies with activity level (eg. in small intestine)
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29
Q

Sinusoids

A
  • Larger pores, often larger diameter vessels with thinner or discontinuous BM
  • Permit rapid exchange of larger solutes
  • Found in liver, bone marrow, spleen, and lymph nodes
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30
Q

Capillary Beds and Control of Blood Flow

A
  • Capillary beds function as networks - not just equipped to change diameter, but arterials can adjust the flow of blood into the capillary beds
  • Collateral arteries form ARTERIAL ANASTAMOSES (flowing together), where the tissue receives blood from two sources in places such as the brain, heart and kidneys
  • Metarteriole and thoroughfare channel are more direct routes from arteriole to venule
  • PRECAPILLARY SPHINCTER: Smooth muscle surrounding entrance to capillaries that adjusts flow
  • ARTERIOVENOUS (AV) ANASTOMOSES can shunt blood from arteries to veins (ie. skin and erectile tissue)
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31
Q

Vasodilation and Vasoconstriction

A

-Vascular resistance is altered by contraction/relaxation of the tunica media
-NO, CO2 triggers VASODILATION, decreased vascular resistance in arterioles, which increases blood flow through pressure within a capillary bed, further enhancing molecular exchange
-Sympathetic input: Circulation NE from the adrenal glands alters vascular resistance in arterioles
+Causes vasoCONSTRICTION, increased VR in most vessels (eg. skin and GI tract)
+Causes vasoDILATION, decreased VR in some vessels (skeletal muscles)

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32
Q

Tissue Capillary Density

A
  • Varies between tissues, depending on the overall metabolic demand of the tissue
  • The greater the density of capillary beds, the greater the surface area for metabolic exchange
  • HIGH in cardiac muscle, kidney, liver, and skeletal muscle
  • LOW in dense CT
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33
Q

Structure of Veins

A

-65-70% of blood volume, about 3.5 L in venous system
-Sympathetic stimulation of venous smooth muscle causes venoconstriction and moves blood out of the blood reservoir into arteriolar/capillary systems
-Venules receive blood from capillary beds
+Postcapillary venules are endothelium, basal lamina, and pericytes
+Primary site of action of vasoactive agents such as histamine and serotonin
+Muscular venules have a thin tunica media and tunica adventitia
-MEDIUM SIZED VEINS: Thin tunica media, few smooth muscle fibres, tunica externa thickest
-LARGE VEINS: Largest diameter, relatively thin tunica media, relatively thick tunica externa

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34
Q

Venous Valves and the Skeletal Muscle Pump

A
  • BP in veins is too low to overcome gravity
  • Venous valves formed by infolding of tunica intima
  • Particularly numerous in veins which conduct blood against gravity, such as those of the lower limbs
  • Contraction of surrounding skeletal muscle compresses veins, forcing venous blood back to the heart
  • Backflow of blood is prevented by valves
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35
Q

Distribution of Veins

A
  • DEEP VEINS accompany systemic arteries; drain deep structures of limbs, head, thorax, abdomen, pelvis
  • SUPERFICIAL VEINS are subcutaneous, drain superficial tissues; no accompanying arteries
  • Shunting of blood between these networks functions in temperature regulation
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36
Q

Organization of Systemic Arteries

A
  • ASCENDING AORTA: Right and left coronary arteries supply the heart
  • ARCH OF AORTA: 3 branches supply the head, neck, shoulders, upper limbs
    1. Brachiocephalic trunk (short vessel that branches)
    a. Right subclavian artery
    b. Right common carotid artery
    2. Left common carotid artery
    3. Left subclavian artery
  • DESCENDING AORTA
    1. Thoracic aorta
    a. Paired visceral branches supply thoracic viscera
    b. Paired parietal branches to chest wall
    2. Abdominal aorta
    a. Unpaired visceral branches supply the digestive tract
    b. Paired parietal branches supply body wall and contained organs
    3. Ends as right and left common iliac arteries
    4. Right and left internal iliac arteries supply pelvis
    5. Right and left external iliac arteries supply legs
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37
Q

Organization of Systemic Veins

A
  • Venous blood returns to the right atrium via the SVC, IVC and coronary sinus
  • SVC drains blood from structures superior to the diaphragm
    1. Right and left subclavian veins drain upper limbs
    2. Right and left internal, external jugular veins drain head and neck
    3. These unite, forming the right and left branchiocephalic veins
    4. Right and left branchiocephalic veins unite, forming superior vena cava
  • IVC drains blood from structures inferior to the diaphragm
    1. Right and left external iliac veins receive blood from legs
    2. Right and left internal iliac veins drain pelvic structures
    3. Unite forming right and left common iliac veins
    4. Unite forming IVC, which carries the blood through the abdominal wall back to the right atrium
    5. Paired veins drain posterior body wall and retropaeritoneal organs
    6. Hepatic veins drain liver into IVC
    7. Hepatic portal system drains digestive tract to LIVER - blood needs to be processed and balanced first, then by the hepatic veins to the IVC
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38
Q

Lymphatic System

A
  • Anatomically diffuse system of cells, tissues and organs
  • Functions to protect the body from disease
  • Distinguished self and nonself on the basis of recognition/nonrecognition of cell surface molecules
  • Destroys/inactivates nonself
  • NONSELF: Virally-transformed, cancerous cells; transplants, pathogens (bacteria, viruses, parasitic worms)
  • Contributes to the control of ISF composition and volume
  • Alternate route of macromolecular transport, especially lipid transport from digestive surfaces
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39
Q

Components of the Lymphatic System

A

-LYMPH: Interstitial fluid, lymphocytes
-LYMPHATIC VESSELS: Originate as blind vessels in peripheral tissues, deliver lymph to venous system
-LYMPHOID TISSUES: Lymph nodules of the MALT (mucosa-associated lymphoid tissue), including tonsils
+CT dominated by lymphocytes
+In some places, they form very large structures that can be seen by the naked eye
-LYMPHOID ORGANS: Bone marrow, thymus, spleen, and lymph nodes

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40
Q

Composition of Mucous Membranes

A
  • EPITHELIAL component varies: simple, stratified, or transitional
  • LAMINA PROPRIA: loose areolar CT, contains BVs, nerves, lymphatics, and cells of lymphatic systems
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41
Q

Mucous Membranes

A
  • Line all passageways that open to the exterior (digestive, respiratory, reproductive, urinary tracts)
  • First line of defense against disease
  • Form a physical barrier to pathogens
  • Moist, lubricated by exocrine glands - fluid often has acidic or antibacterial properties to help with protection
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42
Q

Lymphatic vs. Vascular Capillaries

A

Lymphatics are…

  • Larger in XS, thinner walls
  • Discontinuous basement membrane, epithelium may be fenestrated, acting as a quasi barrier between ISF and lymph
  • Valves created by overlapping endothelial cells - one way flow and lymphocytes because the hydrostatic pressure is lower in the lumen than in the ISF (flows into the lumen)
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43
Q

Larger Lymphatic Vessels

A
  • Similar to veins, but valves are closer together (thinner walls)
  • Skeletal muscle pump assists lymph movement
  • Pressure so low that you cannot move against gravity, so it takes advantage of this pump
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44
Q

Superficial vs. Deep Lymphatic Vessels

A

-Collect lymph from lymphatic capillaries

-Superficial lymphatics travel with superficial veins
+Subcutaneous loose CT, loose CT of mucous membranes

-Deep lymphatics travel with deep veins
+Collect lymph from limbs, pelvis, abdomen, and thorax

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45
Q

Lymphatic Vessels Converge

A

Form LYMPHATIC TRUNKS with regional drainage

  • Lumbar trunks (lower limb, abdominopelvic body wall)
  • Intestinal trunks (abdominopelvic viscera)
  • Bronchomediastinal trunks (thoracic viscera)
  • Subclavian trunks (upper limb)
  • Jugular trunks (head and neck)
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46
Q

Lymph Drains into Venous Blood

A

TRUNKS UNITE

  • CISTERNA CHYLE: Accepts lymph from lumbar and intestinal trunks
  • THORACIC DUCT: Ascends in thorax, arches left, at the next receives lymph from subclavian, jugular, mediastinal trunks, empties into left venous angle (largest vessel in the body)
  • RIGHT LYMPHATIC DUCT formed by the union of the right subclavian, jugular and mediastinal trunks, empties into right venous angle
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47
Q

Lymphocytes

A
  • Respond to antigen and initiate an immune response
  • ANTIGEN may be a soluble peptide, polysaccharide or toxin; may be present on the surface of an infectious organism, foreign tissue or transformed tissue
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48
Q

Lymphocytes: Derivation and Distribution

A
  • Lymphocytic stem cells produced in bone marrow have two fates
    1. Remain in bone marrow and divide to produce NK (natural killed) and B cells
    2. Migrate to thymus and mature into T cells
  • Subpopulations of B and T cells are programmed to recognize specific antigens, and respond only to these antigens, and no other
  • Progeny of a given B or T lymphocyte will have the same antigen specificity
  • The initial programming does not require the presence of the specific antigen
  • For any given foreign antigen, there should be a lymphocyte capable of recognizing it and mounting a defense against it
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49
Q

T Cells

A
  • Responsible for SPECIFIC IMMUNITY (80%)
  • CYTOTOXIC T CELLS are responsible for CELL MEDIATED IMMUNITY and attack antigen directly
  • Respond to virus-infected cells, transformed cells, foreign cells (transplants) and fungi in an ANTIGEN-SPECIFIC MANNER
  • Kill target cell directly, eg. by use of performs or induction of apoptosis
  • REGULATORY T CELLS (helper and suppressor) modulate immune response of both T and B cells
  • MEMORY T CELLS allow for more rapid and severe response in second response
  • Activation requires the antigen be presented on the surface of an ANTIGEN-PRESENTING CELL (APC), such as a macrophage
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50
Q

B Cells

A
  • Responsible for SPECIFIC IMMUNITY (10-15%)
  • Can recognize antigen directly, without APCs
  • With antigen exposure, differentiate into PLASMA CELLS, which produce antibodies
  • Requires cytokines produced by activated helper T cells
  • Plasma cells produce and secrete soluble antibodies, largely in response to bacteria
  • Thus responsible for ANTIBODY-MEDIATED or HUMORAL IMMUNITY
  • ANTIBODIES are soluble proteins that bind antigen on subsequent exposure and mark it for phagocytosis
  • MEMORY B CELLS elicit more rapid and severe response on second exposure
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51
Q

NK Cells

A
  • Responsible for NONSPECIFIC IMMUNITY (5-10%)
  • Nonspecific attack of foreign, cancerous and virus-infected cells
  • Only recognize NONSELF and attack without specificity
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52
Q

Thymus

A
  • Nodular organ posterior to the sternum
  • Largest, most active in youth –> Decrease in size and activity with age
  • Left and right lobes with LOBULES that are separated by SEPTAE of capsule
  • Each lobule has a cortex and a medulla, which are functionally distinct
  • Prenatally, multi potential lymphoid stem cells from bone marrow popular thymus
  • Stem cells of cortex divide rapidly, are educated; those that recognize self antigen are eliminated to help avoid auto-immune issues
  • Blood-thymus barrier prevents premature stimulation of developing T cells in cortex by circulating antigens
  • Cells migrate to the medulla, leave the thymus by blood or lymphatics for distribution throughout the body (either through capillaries of the lymph or efferent blood)
  • T cells do not initiate immune responses within thymus
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53
Q

Lymphoid Tissue

A
  • CT dominated by lymphocytes
  • MALT lymphoid nodules in loose CT of mucosa
  • No fibrous capsule delineates nodules
  • Germinal centre contains activated, dividing lymphocytes - bright center and dark surround, which is full of inactive lymphocytes
  • GUT ASSOCIATED LYMPHOID TISSUE (GALT)
  • Also BALT (BRONCHIAL) of respiratory system and MALT of genitourinary system
  • Unactivated lymphocyte has very little cytoplasm and most of its cell body is nucleus - dark cells that do not let much light through
  • When they differentiate into plasma cells, they become much larger and more active; with increased volume they transmit more light
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54
Q

Gut Associated Lymphoid Tissue

A
  • Lymphoid nodules aggregate to form tonsils, which guard the pharynx
  • Aggregate lymphoid nodules of small intestine, and vermiform appendix (in the shape of a worm)
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55
Q

Structure of Lymph Nodes

A

-Function: In-line filters which cleanse lymph before it reaches venous system
-Dense fibrous CT capsule with trabeculae, reticular fibre stroma
+TRABECULAE go in from the capsule and subdivide the capsule into smaller units
-PARENCHYMA organized into a cortex and medulla
-Afferent lymphatics enter opposite hilus
-Lymph percolates through cortical, trabecular, and medullary sinuses lined by discontinuous endothelium
+Wide spaces with incomplete walls to help the lymph move through giving as much exposure as possible to the lymph node making its way to the efferent lymph vessel
-Hilus with efferent lymph vessel (vessels, arteries and nerves)
+HILUS is the area of an organ where all the stringy stuff enters and exits (VANL)

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56
Q

Cells of Lymph Nodes

A
  • Node contains B cells, T cells, dendritic cells (specialized to lymph nodes) and macrophages, etc
  • Site of local immune responses
  • SUPERFICIAL CORTEX: Here B cells organized into nodules
  • DEEP CORTEX contains most of the T cells of the lymph nodes
  • Medulla consists of medullary cords (mostly plasma cells) and sinuses
  • Lymph nodes enlarge with formation of germinal centers, proliferation of lymphocytes
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57
Q

High Endothelial Venules

A
  • Deep cortex of lymph nodes contains usual post-capillary venules
  • ENDOTHELIUM CUBOIDAL, not squamous
  • Circulating lymphocytes bind to adhesion molecules of the HEVs, cross into lymph of deep cortex, thus populate node
  • With stimulation and proliferation, T cells leave node via lymph and circle body to patrol for antigen and clean it up so it can protect
  • Plasma cells of medullary cords secrete their antibodies into the efferent lymph
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58
Q

Spleen

A
  • Fist-sized organ located in upper left quadrant of abdomen
    1. Functions for blood like lymph nodes for lymph; ie. initiates immune responses to antigens circulating in the blood
    2. Removes aged or abnormal blood cells through phagocytosis
  • RBCs have half life of about 120 days and so they need to be removed as they age - the spleen is architecturally set up to get rid of the bad RBCs (as well as aged platelets)
  • Splenic arteries, veins, lymphocytes, and nerves enter/exit at hilus
  • Spleen has only efferent lymphatics
  • Dense fibrous CT capsule and trabeculae
  • Splenic arteries branch as trabecular arteries
  • No cortex, medulla or lobules
  • Reticular fibre stroma
  • Parenchyma consists of red pulp with scattered islands of white pulp
  • Splenic arteries enter hilus and branch with trabeculae into white pulp
  • White pulp is rich lymphocytes
  • Lymphocytes of the white pulp initiate immune responses to blood-bourns pathogens
  • Blood enters sinusoids of red pulp, which is rich in RBCs, macrophages and functions to remove old RBCs, platelets, particulate matter from blood
  • Blood collects in venules, trabecular, splenic veins, and leaves spleen
59
Q

Functions of Skin

A
  1. Barrier - mechanical, permeability, UV
  2. Immuniological - contains APCs
  3. Homeostatic - body temperature, water loss
  4. Sensory
    - Pain - tissue damage, which the brain perceives as pain (nociception)
    - Touch - light grazing
    - Pressure - deeper movement of the tissue
    - Vibration - distinct receptors that respond to high frequency vibration of the surface of the skin
  5. Endocrine - activation of vitamin D
  6. Excretory - exocrine secretion of sweat, sebaceous and apocrine glands
  7. Drug delivery - lipid-soluble substances such as nicotine, steroid hormones, anti-nauseant delivered via a patch
60
Q

Skin Overview

A

-Organ covering all external surfaces ranging from 5mm in thickness
-Continuous with mucous membranes at body opening
-Consists of TWO layers
1. Epidermis
2. Dermis
(3. Subcutaneous layer/hypodermis/superficial fascia - that is not actually part of the skin)
-Accessory Structures of Skin
1 .Hair
2. Nails
3. Exocrine glands

61
Q

Layers of Skin

A

EPIDERMIS

  • Stratified squamous keratinized epithelium
  • Variety of cell types
  • Consists of 4 or 5 layers (depending on the part of the body)
  • THICK SKIN is hairless, on palms and soles (5 layers)
  • THIN SKIN is elsewhere and usually has hair (4 layers)

DERMIS

  • Underlying CT
  • Papillary layer
  • Reticular layer
62
Q

Epidermis: Layers

A

From SUPERFICIAL to DEEP

  1. Stratum corneum - layer of dead cells at the surface of the body
  2. Stratum lucidem - only in thick skin, lucid and allows light to go through very easily
  3. Stratum granulosum - granules
  4. Stratum spinosum - spiny cell layers
  5. Stratum basale or germinativum - rapid mitosis, cells of skin are regenerating to replace ones lost as surface of skin
  6. Dermis
63
Q

Epidermis: Cells

A
  1. Keratinocytes
  2. Merkel Cells
  3. Langerhans Cells
  4. Melanocytes
64
Q

Keratinocytes

A

EPIDERMIS CELL
-Predominant cell type
-Throughout epidermis; arise in stratum basal (through mitosis in stratum basale), migrate superficially to be shed from stratum corner at skin surface
+Shed 4-6 weeks after formation
+Found in all layers of the skin
+Keratin ONLY found in these cells
-Produce keratin, contribute to epidermal water barrier

65
Q

Merkel Cells

A

EPIDERMIS CELL

  • In stratum germinativum of hairless skin
  • THICK skin only
  • Vesicles contain neuroactive chemicals
  • Released with touch, stimulate afferent nerve endings
66
Q

Langerhans Cells

A

EPIDERMIS CELL

  • In stratum spinosum
  • In epidermis of keratinized skin, mucous membranes, superficial regional lymph nodes
  • APCs: Phagocytose, process antigen, and present epitopes to lymphocytes in regional nodes
67
Q

Melanocytes

A

EPIDERMIS CELL
-In stratum germinativum, cell processes extend to stratum spinosum
-M:K 1:4-1:10 depending on body region
-Produce melanin granules and melanosomes
-Transferred by pigment donation to adjacent keratinocytes, shield nuclei from UV radiation
+Melanin accumulates between nucleus and source of UV radiation to shield - need it less where the sun don’t shine
-Degraded over time by lysosomes of keratinocytes
+By the time that keratinocytes shed from the skin, they are colorless because the melanin degrades over time because it is really only needed during mitosis

68
Q

Epidermis: Stratum Germinativum

A

-Basal cells dominate
+Keratin produced on free ribosomes
+Keratins assembled into keratin intermediate filaments - TONOFILAMENTS
-Desmosomes and hemidesmosomes form, connecting cells via the tonofilaments to adjacent cells and basement membrane (respectively)
-Melanocytes interspersed - regional variations
-Merkel cells
-Epidermal ridge - fingerlike extensions of epidermis peaking into the dermis to increase surface area, which increases the number of hemidesmosomes, which makes more secure contact
+Improves mechanical contact between layers

69
Q

Epidermis: Stratum Spinosum

A

-Spiny due to appearance under LM with cell shrinkage and desmosomes
-Keratinocytes start to produce KERATOHYALIN GRANULES on their free ribosomes, which contain intermediate filament-associated proteins to reinforce and strengthen bundles of keratin
-MEMBRANE-BOUND LAMELLAR GRANULES contain pro-barrier lipids and begin to form here on rough ER
+Lipoproteins that will be secreted and function extracellularly
+End up forming majority of lipid barrier for epidermis
+Fill in spaces between adjacent cells as a lipid barrier to hold the water in - permits skin to be such a good water barrier
-Antigen-presenting Langerhans cells in this layer
-Tissue is dehydrated, so cells shrink and pull away from each other –> would expect gap between adjacent cells; but the gaps here have cell colored extensions between cells (SPINES)
+Despite hydration they maintain physical contact thanks to desmosomes

70
Q

Epidermis: Stratum Granulosum

A
  • Flattened, granule-packed cells which still contain nuclei and organelles (look poxy due to granule spots)
  • Lamellar granules release lipid contents by exocytosis into intercellular space to form the epidermal water barrier
  • KERATINIZATION produces SOFT keratin - dead cells packed with strong protein
71
Q

Keratinization

A
  • Over a 2-6 hour period, cells die at the junction between the stratum granulosum and the next (stratum lucidem or corneum)
  • Conversion of granulocytes into cornified cells
  • Intermediate filament-associated proteins of the keratohyalin granules promote the aggregation of certain filament into TONOFIBRILS, which terminate in desmosomes; thus maintains cohesion and resists abrasion
  • Breakdown of nucleus and other organelles, thickening of cell membrane, and acidification of cytoplasm
72
Q

Epidermis: Stratum Lucidum

A
  • THICK SKIN ONLY
  • Dense layer of flattened, protein-packed cells
  • Particularly translucent at this point of keratinization
  • Some consider it a component of the stratum corner that is only visible in the thicker epidermis of thick skin
73
Q

Epidermis: Stratum Corneum

A

-Consists of SOFT keratin
-Cells dead, flattened, densely packed with keratin tonofibrils, tightly bound together, and low pH (discouraging bacterial growth)
-Keratinocytes shed as pH-dependent enzymatic activity breaks down desmosomes
+As pH drops to critical point, cells are loosened from surface of skin and bye bye cells
-Surface dry and water resistant
-Insensible perspiration - small amount of tissue fluid lost through evaporation across surface of the skin
-Cells remain here for about 2 weeks before shedding

74
Q

Skin Colour

A

DERMAL BLOOD SUPPLY

  • Density of underlying blood vessels –> The richer the more colour
  • Colour of blood flowing through vessels –> cyanotic - turning blue when blood deoxygenated

CAROTENE

  • Accumulates within keratinocytes and underlying adipocytes
  • Can be converted to vitamin A

MELANIN

  • Melanin and racial coloring
  • Melanin and tanning
  • Colour not about the number of melanocytes, but the activity of the cells –> more active, more colour
75
Q

Dermis

A

PAPILLARY LAYER
-Loose CT
-Thinner, more superficial layer
-EPIDERMAL RIDGES and DERMAL PAPILLAE increase SA between epidermis and dermis
-Dermal papillae facilitate nutrient exchange and to improve adhesion - more SA = more hemidesmosomes = stronger contact
-Dermal ridges present in THICK skin to further increase SA between dermis and epidermis
+Gross increases give fingerprints, which are the dermal ridges of thick skin; microscopically it is the same in thin and thick skin

RETICULAR LAYER
-Dense, irregular CT

76
Q

Blood Supply to the Skin

A
  • CUTANEOUS PLEXUS - the junction between subcutaneous (hypodermis) and dermis layers
  • PAPILLARY PLEXUS - within the dermal papillae, where gas exchange and nourishment occur
  • AV ANASTOMOSES - control heat loss through the shunting of blood between arterial and venule
77
Q

Nerve Supply to the Skin

A

SYMPATHETIC INNERVATION

  • ARRECTOR PILI cause hairs to stand up with contraction
  • Glands
  • Vascular smooth muscle

SOMATIC SENSORY INNERVATION

  • Free nerve endings (no myelin)
  • Expanded and encapsulated nerve endings - thermoreceptors, mechanoreceptors, and nociceptors - respond to specific stimuli and inform nervous system about these things impending on our body surface

NO PARASYMPATHETIC INNERVATION

78
Q

Subcutaneous Layer

A
  • AKA hypodermis or superficial fascia
  • Loose areolar to adipose tissue that is largely responsible for the movement of skin
  • Especially in kids - SA:Volume is great in kids, and so not as good because they lose heat more easily
  • Distribution changes at puberty
79
Q

Hair Components

A
  • HAIR FOLLICLES: Invaginations of epidermal epithelium extending through dermis into hypodermis
  • DENSE CT SHEATH surround follicle that provides attachment for arrector pili
  • HAIR BULB: Terminal dilatation of hair follicle that sits on and surrounds the dermal papilla
  • DERMAL PAPILLA: CT containing blood vessels and nerves, which nourish growing hair
  • HAIR MATRIX: Epithelial cels which produce hair, containing basal cells and melanocytes; site of mitosis leading to growing hair
80
Q

The Hair

A

DERIVED FROM HAIR MATRIX MELANOCYTES AND BASAL CELLS

  • MEDULLA contains SOFT keratin and is flexible
  • CORTEX contains HARD keratin and is stiffer
  • CUTICLE is the superficial single layer of flattened, keratinized cells
81
Q

The Follicle

A
  • INTERNAL ROOT SHEATH: Transient structure that doesn’t extend to surface; derived form hair matrix
  • EXTERNAL ROOT SHEATH: Continuous with epidermis
  • GLASSY MEMBRANE: Thickened basement membrane, derived from dermis
  • CT SHEATH: Derived from dermis
82
Q

Hair Growth Cycle

A

CYCLE

  1. ACTIVE PHASE: Hair grows at the same rate (0.33 mm/day), but the duration of the active phase is what makes the difference
  2. REGRESSION/INVOLUTION: Hair growth stops and shedding occurs
  3. RESTING PHASE: Loosening of attachment in follicle
  4. REACTIVATION: Loss of club hair
    - About 50 hairs lost a day in adults
    - Affected by drugs, diet, pregnancy, radiation, age and hormones
83
Q

Types of Hair

A
  1. VELUS HAIR: Very fine
  2. TERMINAL HAIR: Coarse and more heavily pigmented

-Follicles hormonally responsive - at puberty, pregnancy, menopause and old age can change the follicle to produce one over the other

84
Q

Hair Colour

A
  • Melanocytes at the papilla
  • Melanin type and density determines color
  • Genetically determined
  • Melanin production decreases with age
85
Q

Sebaceous Glands

A
  • Distribution: Wherever there is hair
  • Function accelerates dramatically at puberty (increased secretion)
  • Duct opens into hair follicle
  • Structure: Simple alveolar to simple branched alveolar (acinar) glands, depending on the follicle size
  • SEBUM is released by holocrine secretion (entire cell is shed)
  • FUNCTION: Lubricates and protects keratin of hair and skin
  • Arrector pili muscle promotes secretion with the sebaceous gland, so when it contracts, it gives the gland a little squeeze to promote secretion
  • Implicated in acne
86
Q

Sweat Glands

A
  • Simple coiled tubular glands and secrete by the MEROCRINE method (exocytosis)
  • Myoepithelial cells associated with secretory portion
  • Types
    1. Merocrine Sweat Glands
    2. Apocrine Sweat Glands
87
Q

Merocrine Sweat Glands

A
  • AKA Eccrine sweat glands
  • Numerous, widely distributed and functional from birth
  • Secretory portion in dermis or superficial hypodermis
  • Ducts open onto skin surface
  • Secretion watery ultrafiltrate of blood
  • FUNCTION: Thermoregulation and excretion
88
Q

Apocrine Sweat Glands

A
  • Initially thought to secrete via apocrine method, but actually merocrine
  • Distribution: Axillae (armpits), areolae, and groin
  • Functional at puberty
  • Secretory portion in dermis and hypodermis
  • Ducts open into hair follicles
  • Odour with bacterial action (–>BO)
  • Viscous secretion
  • In other animals, they secrete pheromones, but in humans the function is iffy
89
Q

Hair Accessory Structures: Nails

A

-Nail plate highly compacted and keratinized
-Nail bed underlies nail plate
+Highly vascular in nature
-Attachment: Nail root and bed bound to periosteum of distal phalanx (last bone of finger)
-Nail matrix: Epithelium underlying nail root that extends distally to LUNULA (site of mitosis, produces nail plate)
-With growth, nail slides distally
-Appearance altered with metabolism and disease

90
Q

Skin with Age

A
  • Fewer melanocytes - pail skin, reduced tolerance for skin exposure
  • Fewer active follicles - thinner, more sparse hairs
  • Reduced skin repair - skin repairs proceed more slowly
  • Decreased immunity - Reduced number of Langerhans cells
  • Thin epidermis - slow repairs decrease vitamin D production
  • Reduced sweat gland activity - tendency to overheat
  • Thin dermis - sagging and wrinkling due to fiber loss
  • Reduced blood supply - slower healing and tendency to overheat
  • Dry epidermis - decreased sebaceous and sweat gland activity
  • Changes in distribution of fat and hair - due to reductions in sex hormone levels
91
Q

Breast

A

-Nipple - opening of LACTIFEROUS DUCTS
-Areola - heavily pigmented and large sebaceous glands
-15-25 lobes per mammary gland that are each drained by a lactiferous duct
-Lactiferous sinus is an expansion of lactiferous duct, where milk is stored
-Each lobe is subdivided into lobules, which are secretory units made up of secretory cells and duct system that produce milk and conduct it towards the surface
-Pectoral fat pad made of subcutaneous adipose tissue
-In functional female, the breast is associated with SUSPENSORY LIGAMENTS of dense CT that extend from dermis to pectoral epimysium
+Act as mechanical support to support weight of breast

92
Q

Inactive vs. Lactating Breast

A
  • Secretory portions grow as pregnancy continues and become larger until they are functional at the time of delivery
  • Junction between duct and secretory portion of the mammary gland
  • Secretory cells secrete protein by exocytosis and the lipids by apocrine method
  • Milk is initially high in protein (antibodies) and over time the protein portion drops off and mostly just delivers lipids
  • Apoptosis of secretory cells occurs once the baby is done breast feeding and goes back to resting size
93
Q

Lymphatic Drainage of the Breast

A

-Axillary tail of breast that extends into axilla –> not symmetrical, found in the superior lateral quadrant with excess tissue
-Subareolar lymphatic plexus
-LATERALLY, lymph drains into AXILLARY lymph nodes and subclavian trunk
+From center to periphery
+In a healthy breast, the lymph drains into axilla –> subclavian trunk –> LEFT venus angle with the thoracic duct or RIGHT venus angle with lymphatic duct
-MEDIALLY, some lymph drains into PARASTERNAL lymph nodes and bronchomediastinal trunk
+Not palpatable
+Harder to detect is they become enlarged
+Lymph drains through these and ultimately collects in the bronchomediastinal trunk –> venus angle
-Lymphatic drainage of the breast and breast cancer

94
Q

Articulations

A
  • Occur wherever two bones meet
  • Movement occurs at articulations, but not all permit movement
  • Classified structurally, by what tissue joins the articulating bones
  • Classified functionally, by the range of movement permitted
    1. Synarthrosis - NO movement
    2. Amphiarthrosis - LITTLE movement
    3. Diarthrosis - FREE movement
95
Q

Synarthroses

A

Immovable

FIBROUS SYNARTHROSES

  • Bones joined by dense irregular CT
  • SUTURE between bones of skull, GOMPHOSIS between each tooth and its bony socket

CARTILAGENOUS SYNARTHROSES

  • Bones joined by cartilage
  • SYNCHONDROSIS is the cartilage joining two bones together; exists at the epiphyseal plate of a growing bone, and first costosternal joint

BONY FUSION

  • Two bones become one
  • SYNOSTOSIS where the bones fuse, such as in the skull, sacrum, hip bones, sternum, vertebrae, and mature long bones
96
Q

Amphiarthrosis

A

Permit slight movement

FIBROUS AMPHIARTHROSIS

  • Bones joined by a ligament or band of CT
  • SYNDESMOSES at the distal tibiofibular joint

CARTILAGINOUS AMPHIARTHROSIS

  • Bones joined by a wedge of cartilage
  • SYMPHYSES at the intervertebral disks and symphysis pubis
97
Q

Diarthrosis

A

Free movement
AKA Synovial Joints

FIBROUS JOINT CAPSULE

  • Encloses joint space
  • Fused with periosteum of the bone proximally and distally
  • Closed because it is filled with fluid

ARTICULAR CARTILAGE

  • Covers articulate surfaces
  • Hyaline, smooth cartilage
  • Decreases friction

SYNOVIAL MEMBRANE

  • Covers all internal, nonarticular surfaces
  • Secretes synovial fluid
  • Has a layer of epithelium and underlying CT
  • Synovial fluid fills the joint cavity to decrease friction (lubricant and shock absorber)

JOINT CAVITY

  • Contains synovial fluid
  • Lubricant
  • Shock absorber
  • Medium for solute transfer between blood and cartilages, so cartilage can get its nutrients and shit
98
Q

Diarthrosis Accessory Structures

A

-ARTICULAR DISCS or menisci, such as medial and lateral menisci of knee joint; discs of fibrocartilage that improve continuity of the articulating bones so improve stability
-FAT PADS to accommodate joint movement
-TENDONS to help stabilize joint
-BURSAE
-INTRINSIC LIGAMENTS: thickenings of the joint capsule across certain aspects of the joint
-EXTRINSIC LIGAMENTS
+Intracapsular - joins two bones with no connection to ligament, inside the joint capsule
+Extracapsular - outside joint capsule

99
Q

Bursae

A

Diarthrosis Accessory Structure

  • Sacks of synovial membrane containing synovial fluid
  • Decreasing friction while allowing movement of two structures relative to each other
  • Facilitate relative movement between structures
  • May be subcutaneous or subtendinous
  • When inflamed, results in bursitis
100
Q

Stability vs. Mobility of Joints

A

-Stability is inversely proportional to mobility
-Both are influenced by
+Shape of articulating surfaces
+Capsule
+Ligaments (limit mobility, promote stability)
+Tone of surrounding muscles
+Other tissues around the joint

101
Q

Functional Classification of Synovial Joints

A

MOVEMENT

  • Gliding - linear motion
  • Angular movement
    1. Uniaxial
    2. Biaxial
    3. Triaxial - two horizontal axes and long axis
102
Q

Structural Classification of Synovial Joints

A
  1. GLIDING JOINT - uniaxial, intercarpal joints
  2. HINGE JOINT - uniaxial, elbow joint
  3. PIVOT JOINT - uniaxial, atlantoaxial jointl joint in the head to shake no on the long axis of the head
  4. ELLIPSOIDAL JOINT - biaxial, radiocarpal joint; movement along two horizontal axes but not long axis
  5. SADDLE JOINT - biaxial, 1st metacarpophalangeal joint; convex in one direction and concave in the other
  6. BALL-AND-SOCKET JOINT - triaxial, shoulder joint
103
Q

Respiratory System: Overview

A

-Functions to facilitate the exchange of gases between air and blood
-CONDUCTING PORTION
+Largely lined by respiratory epithelium that conditions air - filters, warms and humidifies
+Includes nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles
-RESPIRATORY PORTION
+Gas exchange occurs across the respiratory membrane to separate air from blood and this is where gas exchange occurs
+Includes respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli

104
Q

Mucous Membranes of the Conducting Portion

A
  1. Respiratory mucosa

2. Oral mucosa

105
Q

Respiratory Mucosa

A
  • Mucous membrane of the conducting portion that is specialized for conditioning air
  • Lines the conducting portion of the respiratory system: nasal cavities, nasopharynx, trachea, bronchi and bronchioles
  • Mucus traps particles and cilia beat toward pharynx
  • Conditions inspired air and occurs especially in the nasal cavity
  • Consists of two layers
    1. RESPIRATORY EPITHELIUM - psuedostratified ciliated columnar epithelium with goblet cells
    2. UNDERLYING LAMINA PROPRIA - loose CT that is very vascular because it is constantly losing heat into the air, so the rich blood supply needs to be there
106
Q

Oral Mucosa

A
  • Mucous membrane of the conduction portion
  • Stratified squamous nonkeratinized epithelium
  • In oral cavity, oropharynx and laryngopharynx
  • Parts of the respiratory tract are shared with the digestive tract because it needs more protection than filtering
107
Q

Nasal Cavity

A
  • HARD PALATE forms floor of nasal cavity and roof go the mouth
  • Lined with RESPIRATORY MUCOSA
  • Coarse hairs help trap larger particles
  • Superiorly, the OLFACTORY EPITHELIUM includes olfactory receptor cells
  • Bony (posterior)/cartilagenous (anterior) nasal septum divides nasal cavity into left and right portions
  • Superior, middle and inferior NASAL CONCHAE subdivide nasal cavity and create turbulence in inspired air to stimulate air conditioning
  • Nasal sinuses are air-filled spaces lined by mucous membrane that open into the nasal cavities
108
Q

Olfaction

A

-Olfactory organs in roofs of nasal cavities
-Neuroepithelium and underlying CT (lamina propria)
-Turbulence brings odorants into contact with olfactory organs
+Odorants have to be in a liquid medium and dissolve into the mucous and bind with the receptors that are on the dendritic hairs
-Odorants dissolve in mucus to bind with olfactory receptors and nerves
-Specific receptor binding of odorant causes depolarization
-Axons from olfactory epithelium pass through CRIBRIFORM PLATE as cranial nerve I to synapse on nerves in olfactory bulbs
-Project to primary olfactory cortex, hypothalamus, and limbic system via the olfactory tract
-More than 50 primary smells, different receptor populations on different nerves
-CNS interpretation based on pattern of receptor activation
-Decrease in receptor number and sensitivity with age

109
Q

Pharynx

A

-Throat
-Portions common to both respiratory and digestive systems
-A muscular tube that extends from base of skull to bifurcation of the esophagus and trachea to where the respiratory and digestive tracts diverge
Respiratory System Only
-NASOPHARYNX is posterior to nasal cavity and superior to soft palate
Respiratory and Digestive System
-OROPHARYNX is delineated by soft palate and hyoid bone
-LARYNGOPHARYNX from hyoid bone to bifurcation of esophagus and trachea

110
Q

Nasopharynx

A

-Part of respiratory system only
-Posterior to nasal cavity and superior to soft palate
-Lined by respiratory epithelium
-Contains the opening of the AUDITORY TUBES (physical connection between middle ear and throat) and the PHARYNGEAL TONSIL (adenoids, single midline tonsil that can enlarge and interrupt breathing when people are sleeping)
-SOFT PALATE raised during swallowing to seal off nasopharynx
+Soft palate is the muscle that prevents food from getting into the nasopharynx because when we swallow, the soft palate raises and seals off the nasopharynx

111
Q

Oropharynx

A

-Delineated by soft palate and hyoid bone
HYOID BONE is shaped like a horseshoe and not attached to any other bones
+Position is determined by the muscles that attach the bone
+Supports the floor of the mouth
+Anchors the larynx
-Lined by stratified squamous epithelium
-Contains the PALANTINE TONSILS (paired) and LINGUAL TONSILS (lymphoid)

112
Q

Laryngopharynx

A
  • From hyoid bone to bifurcation of esophagus/trachea

- Lined by stratified squamous epithelium

113
Q

Larynx and its Relationships

A
  • Laryngopharynx opens into the esophagus (digestive) posteriorly and the larynx (respiratory) anteriorly
  • FUNCTIONS
    1. Conducts airs into the trachea
    2. Guards the trachea against the entry of liquids and solids
    3. Produce sounds
  • Opening into the larynx is the GLOTTIS, which is guarded by the EPIGLOTTIS
  • Inferiorly, the larynx opens into the TRACHEA
114
Q

Swallowing

A
  1. Tongue forces compacted bolus into oropharynx
  2. Laryngeal movement folds epiglottis and pharyngeal muscles push bolus into esophagus
  3. Bolus moves along esophagus and larynx returns to normal position
  • EXTRINSIC muscles of the larynx attach it to the hyoid bone above and the sternum below to move the larynx with the throat
  • Elevation of the larynx during swallowing forces the epiglottis over the glottis and guards against the passage of solid or liquid into the airway
115
Q

Larynx and Trachea

A

-Larynx includes two large, unpaired cartilages in addition to the epiglottis: the THYROID cartilage and the CRICOID cartilage
-Larynx is suspended from the hyoid bone by the THYROHYOID MEMBRANCE, a dense CT band
+Muscles are laid on top of this and control position

116
Q

Body Cavities

A
  1. DIAPHRAGM: A muscular sheet (skeletal, voluntary muscle) that separates the other cavities
  2. THORACIC CAVITY has three separate subdivisions
    a. Laterally, right and left PLEURAL cavities that contain the lungs
    b. Medially, the MEDIASTINUM (NOT a cavity), which contains many structures embedded in CT, including heart in its PERICARDIAL CAVITY
  3. ABDOMINOPELVIC (PERITONEAL) CAVITY: Subdivided into two continuous spaces
    a. ABDOMINAL CAVITY containing the abdominal viscera
    b. PELVIC CAVITY containing pelvic viscera
117
Q

Serous Membranes

A

-Line walls of body cavities and their contents
-Consist of MESOTHELIUM (simple squamous) and SUBSERIOUS FASCIA (loose areolar CT)
-Parietal and visceral portions are histologically IDENTICAL and continuous with each other
+PARIETAL lines walls of cavity
+VISCERAL ines contained organs
+SEROUS CAVITY containing transudate (fluid secreted by both portions, lubricant) intervenes

118
Q

Cavities and Their Serous Membranes

A

PLEURAL CAVITY

  • Contains lungs
  • Parietal and visceral PLEURA
  • Transudate: Pleural fluid

PERICARDIAL CAVITY

  • Contains heart
  • Parietal and visceral PERICADIUM
  • Transudate: Pericardial fluid

PERITONEAL CAVITY

  • Contains abdominopelvic viscera
  • Parietal and visceral PERITONEUM
  • Transudate: Peritoneal fluid
119
Q

Mediastinum

A

Bordered LATERALLY by the lungs, ANTERIORLY by the sternum, and POSTERIORLY by the vertebral column

3 subdivisions

  1. ANTERIOR MEDIASTINUM
    - Posterior to sternum and anterior to pericardial sac
    - Thymus, loose CT, blood vessels and nerves
  2. MIDDLE MEDIASTINUM
    - Pericardial sac and contents
  3. POSTERIOR MEDIASTINUM
    - Posterior to pericardial sac and anterior to vertebral column
    - Trachea and primary bronchi, esophagus, great vessels and loose areolar CT
120
Q

Gross Anatomy of the Lungs

A

Superior apex and posterior base

3 Surfaces

  1. COSTAL - adjacent to ribs
  2. MEDIASTINAL - adjacent to mediastinum
  3. DIAPHRAGMATIC - adjacent to diaphragm (base of the lung)

RIGHT LUNG has three lobes - superior, middle and inferior - separated by two fissures - horizontal and oblique
LEFT LUNG has two lobes - superior and inferior - separated by one fissure - oblique; with CARDIAL NOTCH to accommodate the heart

121
Q

Mediastinal Surfaces of the Lungs

A
  • ROOT of the lung consists of the primary bronchi, pulmonary As, Vs, Ns and Ls, all enclosed in CT
  • HILUS of the lung is the region containing the root of the lung
122
Q

Conducting Portion: Organization

A
  • Pharynx –> larynx –> trachea
  • Tracheal rings joined by ANULAR LIGAMENTS
  • Trachea bifurcates at the CARINA at sternal angle into right and left PRIMARY BRONCHI (1 per lung)
  • Right primary bronchus is more vertical than the left and therefore things are more likely to end up here when inhaled; Left is longer because it has to travel further
  • Primary bronchi enter the hilus of the lungs
  • BRONCHIAL TREE
    1. Primary bronchi - 1 per lung
    2. Secondary bronchi - 1 per lung lobe
    3. Tertiary bronchi - 1 per bronchopulmonary segment; eventually branch into bronchioles
123
Q

Bronchopulmonary Segments

A
  • Lung tissue supplied by a given tertiary bronchus
  • Portion of lobe that has its own dedicated air, blood and nerve supply as well as lymphatic drainage
  • Right lung has about 10
  • Left lung has 8-9
124
Q

Histology of Trachea

A
  • Respiriatory mucosa
  • C-shaped TRACHEAL CARTILAGES and elastic ANULAR ligaments
  • TRACHEALIS MUSCLE relaxes with sympathetic stimulation –> bronchodilation
125
Q

Histology of Bronchi

A
  • Amount of cartilage decrease through the primary, secondary and tertiary bronchi
  • Tertiary branch repeatedly to form bronchioles
  • Circular layer of smooth muscle appears in bronchi, prominent in bronchioles
126
Q

Histology of Bronchioles

A
  • Cartilage ABSENT
  • Smooth muscle under autonomic control
  • Branching ends as TERMINAL BRONCHIOLES, marking the end of the conducting system and beginning of the respiratory system
127
Q

Pulmonary Lobule

A

Terminal bronchioles –> respiratory bronchioles –> alveolar ducts –> alveolar sacs –> alveoli

  • Respiratory bronchioles lead to individual PULMONARY LOBULES
  • Branches of the pulmonary ARTERIES form capillary beds around alveoli for gas exchange and then coalesce as pulmonary VENULES and then VEINS (which eventually go back to left heart)
  • Bronchial vessels are the nerves supplying lung tissue itself
  • Smooth muscle of bronchioles gives way to ELASTIC FIBRES surrounding alveoli, assisting in expiration
128
Q

Histology of Alveolus

A
  • TYPE I CELLS (PNEUMOCYTES) form a simple squamous epithelium that line the walls of the alveolus
  • TYPE II CELLS (PNEUMOCYTES) secrete surfactant, which decrease surface tension and maintains alveolar patency (openness)
  • ALVEOLAR MACROPHAGES patrol and phagocytose pathogens
  • RESPIRATORY MEMBRANE is where gas exchange is rapid due to thinness of membrane and lipid solubility of gases - separates air and blood in alveolus
129
Q

Emphysema

A
  • When you exhale, the lungs empty due to elasticity of lung tissue, therefore each alveolus acts like a mini balloon
  • Issue is that the lungs cannot empty properly because the elasticity is iffy, causing stale air to be trapped in the lungs and so it cannot be fully filled with fresh air
130
Q

Vertebra Regions of the Thorax

A
  • CERVICAL REGION has 7 cervical vertebrae (C1-C7)
  • THORACIC REGION has 12 thoracic vertebrae (T1-T12) that articulate with the ribs and contribute to bony thorax
  • LUMBAR REGION has 5 lumbar vertebrae (L1-L5)
  • SACRAL REGION goes from 5–>1 vertebrae (S1-S5) and contributes to the bony pelvis
  • COCCYGEAL REGION goes from 3-5–>1 vertebrae (Co1-Co5)
131
Q

Spinal Curves

A

PRIMARY CURVES

  • Thoracic and Sacral
  • Develop prenatally
  • Curved FORWARD

SECONDARY CURVES

  • Cervical and lumbar (use-dependent curves)
  • Develop postnatally
  • Curved BACKWARD
  • CERVIAL develops with ability to hold head up
  • LUMBAR develops with upright posture (around 12 mos. of age) in attempt to centre weight over hips; critical in balance
132
Q

Anatomy of Typical Vertebra

A

SEE PICTURES

133
Q

Regional Variations in Vertebrae

A

-Structural variations in vertebrae reflet regional specializations in function
-In a ROSTORCAUDAL direction
+Size of vertebral body increases to help with weight bearing
+Diameter of vertebral canal decreases with the spinal cord diameter
+Regional differences in processes reflect the regional differences in function and movement

134
Q

Intervertebral Articulations

A

-VERTEBRAL CANAL houses the spinal cord
-INTERVERTEBRAL FORAMINA are spaces between vertebrae that accommodate spinal nerves
-ZYGAPOPHYSEAL JOINTS plane synovial joints that allow slight gliding movements and join the superior and inferior articular processes of adjacent vertebrae
-INTERVERTEBRAL DISCS are symphyses containing fibrocartilagenous ANULUS FIBROSUS, which joins disc to adjacent vertebral bodies; and the NUCLEUS PULPOUS, the gelatinous core that is largely water
-INTERVERTEBRAL LIGAMENTS
+SUPRASPINOUS and INTERSPINOUS ligaments
+ANTERIOR and POSTERIOR LONGITUDINAL ligaments
+LIGAMENTUM FLAVUM

135
Q

Bony Thorax, Nerve Supply of Thoracic Wall, Arterial Supply of Thoracic Wall, Venous Drainage of Thoracic Wall

A

SEE PICTURES

136
Q

Respiration and the Thoracic Cavity

A

-Increase in thoracic volume occurs with MUSCULAR CONTRACTION (INHALATION)
-Increase in thoracic volume DRAWS AIR into lungs
-Air is expelled from the lungs PASSIVELY with elastic recoil of lung tissue and thorax
+May be assisted by muscular contraction during FORCED RESPIRATION

137
Q

Intercostal Muscles and Thoracic Movements

A
  • Volume of thorax is determined in part by position of ribs
  • Elevation of ribs increases the lateral and AP dimensions of the thorax
  • Depression decreases them
  • INTERCOSTAL MUSCLES join adjacent ribs and take care of this action
  • Three layers
    1. EXTERNAL INTERCOSTAL MUSCLES run hands in pocket direction and act to ELEVATE RIBS
    2. INTERNAL INTERCOSTAL MUSCLES run perpendicular to external and act to DEPRESS RIBS
    3. INNERMOST INTERCOSTAL MUSCLES decrease throax volume and push air out
138
Q

Thoracic Apertures

A

Only ways to get in and out of thorax

SUPERIOR THORACIC APERTURE

  • Borders: T1, 1st ribs, and superior border of manubrium
  • Contains great vessels, trachea and esophagus

INFERIOR THORACIC APERTURE

  • Borders: T12, 11th and 12th ribs, costal cartilages 7-10 and xiphisternal joint
  • Origin of diaphragm
139
Q

Diaphragm

A

-Muscle fibres arranged radially and insert into its CENTRAL TENDON, which is not contractile
-CURA attach the diaphragm to lumbar vertebrae below and act as an anchor on either side
-The IVC, esophagus and aorta pass through the diaphragm
-BLOOD SUPPLY: Superior and inferior PHRENIC arteries and veins
-NERVE SUPPLY: PHRENIC nerves formed by branches of C3-C5 spinal nerves
-Relation to Thoracic Volume
+CONTRACTION –> diaphragm flattens and increases volume
+RELAXATION –> diaphragm domes up and decreases volume

140
Q

Muscles of Respiration

A

INHALATION is active, due to contraction of…

  • External intercostals, which elevate the ribs and sternum, increasing AP and lateral dimensions of thoracic cage
  • Diaphragm, which descends on contraction to increase vertical dimension of thoracic cage
  • Accessory muscles of inspiration elevate ribs during periods of high O2 demand

EXHALATION by be passive, due to recoil of lung tissue and CTs

EXHALATION may be active during forced expiration, due to contraction of the INTERNAL intercostals, which may be assisted by the abdominal muscles

141
Q

Pleural Membranes and Respiration

A
  • Inherent elasticity of lungs permit them to expand as the volume of the thoracic cavity increases and therefore remain in contact with thoracic wall
  • As volume increases, the lungs expand and air is drawn in
  • A PNEUMOTHORAX occurs when there is a hole in the chest wall and the lung collapses, filling the pleural cavity with air
142
Q

Neural Control of Respiration

A

-Rate and depth of breathing matched with tissue demands for O2 delivery and CO2 removal
-Brainstem respiratory rhythmicity nuclei control the basic rate and depth of breathing
+EFFERENT fibres of the INSPIRATORY centre control activity of respiratory muscles via the phrenic and intercostal nerves
+EFFERENT fibres of the EXPIRATORY centre control activity of accessory muscles of expiration
-Modulated by feedback regarding blood gas, pH levels, BP, and lung volume
-Modulated by descending input, both voluntary and involuntary

143
Q

Somatic Innervation: Body Wall and Limbs

A
  • Somatic motor neurons innervate SKELETAL MUSCLE via cell bodies in the VENTRAL GREY HORN of the spinal cord
  • Sensory nerves monitor skin, joints and skeletal muscle via cell bodies in the DORSAL ROOT GANGLIA; axons convey info to dorsal grey horn of spinal cord
  • Axons form peripheral nerves
  • The dorsal and ventral rami are both sensory and motor fibres, therefore they are called MIXED NERVES
  • Axon goes through the ventral horn –> ventral root –> spinal nerve –> ventral ramus

PHM145 Anatomy and Histology (1 decks)

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