Lymph - Lab Flashcards
(28 cards)
Palpation Sites for Arterial Pulses
- Carotid: palpate lateral to trachea, between SCM and larynx
- Radial: palpate lateral wrist, just proximal to base of thumb
- Brachial: palpate medial to biceps tendon in antecubital fossa or mid-humerus
- Dorsalis pedis: palpate dorsal foot, lateral to extensor hallucis longus tendon
- Posterior tibial: palpate posterior to medial malleolus (ankle), between Achilles and tibia
Systole
- Ventricular contraction phase
- Blood is ejected from ventricles into aorta and pulmonary trunk
- Corresponds to high arterial pressure (systolic BP)
Cardiac Cycle (Full Sequence of Events)
-
Quiescent Period (Late Ventricular Diastole)
- All chambers relaxed
- AV valves open, blood flows passively into ventricles
- Ventricles ~70–80% full
- SA node fires near end → triggers next phase -
Ventricular Filling (Phase 1)
a. Rapid filling: AV valves fully open → blood rushes in (occurs durring quiescent period)
b. Diastasis: Slower passive filling as atria and ventricles equalize pressure (occurs durring quiescent period)
c. Atrial systole: Atria contract (P wave) → push final blood into ventricles
→ End-Diastolic Volume (EDV) ~130 mL -
Isovolumetric Contraction (Phase 2)
- Ventricles depolarize (QRS complex) → begin contraction
- AV valves close (first heart sound S₁)
- All valves shut → no volume change yet
- Ventricular pressure rising rapidly -
Ventricular Ejection (Phase 3)
- Pressure exceeds aortic/pulmonary pressure → semilunar valves open
- Blood ejected → stroke volume ~70 mL
- Remaining ~60 mL = End-Systolic Volume (ESV)
- Occurs during ST segment and T wave -
Isovolumetric Relaxation (Phase 4)
- Ventricles repolarize (T wave) → relax
- Semilunar valves close (second heart sound S₂)
- All valves shut → volume constant
- Ventricular pressure drops rapidly
→ Cycle restarts as AV valves reopen once pressure in ventricles < atria
Diastole
- Ventricular relaxation phase
- Ventricles fill with blood from atria
- Corresponds to low arterial pressure (diastolic BP)
Dicrotic Notch
- Small dip in aortic pressure tracing
- Occurs after aortic valve closes
- Represents elastic recoil of aorta and brief backflow
S1 / S2
S1 (lubb)
- First heart sound
- Caused by closure of AV valves (mitral + tricuspid)
- Marks beginning of systole
S2 (dub)
- Second heart sound
- Caused by closure of semilunar valves (aortic + pulmonary)
- Marks beginning of diastole
Pulse presure
- Difference between systolic and diastolic pressure
- Formula: PP = SBP − DBP
- Reflects stroke volume and arterial compliance
Blood Pressure Definitions and Interpretation
- Healthy BP: <120/80 mmHg
- Hypertension: ≥130/80 mmHg (Stage 1); ≥140/90 mmHg (Stage 2)
- Pre-hypertension: 120–129 systolic, and <80 diastolic
- Hypotension: <90/60 mmHg
- Pulse Pressure = Systolic − Diastolic
Examples:
- 118/70 → Healthy (normal systolic and diastolic)
- 140/60 → Isolated systolic hypertension (wide pulse pressure = 80)
- 150/100 → Stage 2 hypertension (pulse pressure = 50)
- 80/40 → Hypotension (pulse pressure = 40)
thymus
- Located in mediastinum, anterior to heart
- Site of T cell maturation
- Ensures self-tolerance via positive and negative selection
- Most active in childhood, shrinks with age (involution)
spleen
- Located in left upper quadrant (LUQ), near stomach
- Filters blood, not lymph
- Removes old RBCs, stores platelets
- Contains white pulp (lymphocytes) → immune surveillance
- Red pulp → phagocytosis of pathogens and debris
2 -> superficial cervical lymph nodes
4 -> Deep cervical lymph nodes
- Located along neck (anterior, posterior, deep cervical chains)
- Drain head and neck regions
- Swell during local infections (e.g., pharyngitis, tonsillitis)
axillary lymph nodes
- Located in the armpit (axilla)
- Drain upper limbs, breast, and thoracic wall
- Important in breast cancer metastasis
intestinal lymph nodes
- Located in mesentery and intestinal wall
- Includes mesenteric, ileocolic, and paraaortic nodes
- Drain intestines and abdominal organs
- Monitor and respond to gut pathogens and antigens
- Support oral tolerance and gut-associated lymphoid tissue (GALT)
inguinal lymph nodes
#1
pharyngeal tonsils
- Located in posterior nasopharynx
- Part of Waldeyer’s ring
- Trap and filter inhaled pathogens
- Contain lymphoid follicles with B and T cells
- Called adenoids when enlarged
#2
Palatine tonsils
- Located in oropharynx, between palatoglossal and palatopharyngeal arches
- Part of Waldeyer’s ring
- Exposed to ingested and inhaled pathogens
- Contain lymphoid follicles for immune activation
- Common site of tonsillitis
#3
Lingual tonsils
- Located at the base of the tongue
- Part of Waldeyer’s ring
- Contain lymphoid tissue to detect pathogens in swallowed substances
- Contribute to local immune defense in oral cavity
- Less commonly infected than palatine tonsils
Lymphatic vessel
thin-walled tubes, similar to blood vessels, that form a network throughout the body to collect and transport lymph fluid
Thoracic Duct
- Largest lymphatic vessel in the body
- Drains lymph from left side of head, neck, chest, left arm, and entire lower body
- Empties into left subclavian vein
- Returns filtered lymph to circulation → maintains fluid balance
- Transports lymphocytes and dietary lipids (chyle)
lymphatic duct = A large lymphatic vessel that drains lymph into the venous system
Right Lymphatic Duct
- Drains right upper quadrant: right arm, right side of head/neck, and right thorax
- Empties into the right subclavian vein (near junction with right internal jugular vein)
- Much smaller than thoracic duct
- Returns lymph to bloodstream → supports fluid balance and immune surveillance
Cisterna Chyli
- Dilated sac at the lower end of the thoracic duct
- Located anterior to L1–L2 vertebrae, just right of the aorta
- Receives lymph from:
- Intestinal trunk (lymph from GI tract)
- Lumbar trunks (lymph from lower limbs and pelvis)
- Acts as a collection reservoir before lymph enters the thoracic duct
- Important for transporting chyle (fat-rich lymph) from intestines
Appendix (Vermiform Appendix)
- Narrow, tube-shaped extension of the cecum (inferior to ileocecal valve)
- Contains lymphoid tissue → contributes to immune surveillance, especially in early life
- May serve as a reservoir for gut flora
- Can become inflamed → appendicitis, often requiring surgical removal
- Located in right lower quadrant (RLQ) of abdomen
Thymus Histology
- Cortex: densely packed with immature T cells (thymocytes) and epithelial reticular cells; site of positive selection
- Medulla: fewer lymphocytes; contains mature T cells, more epithelial cells, and macrophages; site of negative selection
- Thymic (Hassall’s) corpuscles: concentric rings of epithelial reticular cells found only in the medulla; involved in T cell maturation and immune tolerance
Spleen Histology
- Red pulp: filters blood, removes old/damaged RBCs, contains sinusoids and macrophages
- White pulp: contains lymphocytes around central arterioles, functions in immune surveillance and activation of B and T cells
