Lymph - Lab

Question 1

Apical vs. Radial Pulse

Answer 1

Definitions
- Apical pulse: heartbeat heard at apex of the heart, over 5th intercostal space, midclavicular line using a stethoscope
- Radial pulse: palpable pulse felt at the radial artery on the lateral wrist, just proximal to the base of the thumb

Key Points
- Apical pulse reflects actual heart contractions
- Radial pulse reflects peripheral blood flow from heart contractions
- Pulse deficit = apical rate − radial rate → indicates ineffective cardiac contractions

Other Palpable Arteries (not apical)
- Carotid: lateral to trachea, between SCM and larynx
- Brachial: medial to biceps tendon in antecubital fossa
- Dorsalis pedis: dorsal foot, lateral to extensor hallucis longus tendon
- Posterior tibial: posterior to medial malleolus, between Achilles and tibia

Question 2

Systole

Answer 2

• Ventricular contraction phase
• Blood is ejected from ventricles into aorta and pulmonary trunk
• Corresponds to high arterial pressure (systolic BP)

Question 3

Cardiac Cycle (Full Sequence of Events)

Answer 3

One complete heartbeat, consisting of systole (contraction) and diastole (relaxation) of both atria and ventricles.

• Normal length: ~0.8 seconds at 75 bpm
  
  • Atrial systole: ~0.1 sec
  • Ventricular systole: ~0.3 sec
  • Quiescent period (diastole): ~0.4 sec

Question 4

Define Pulse

Answer 4

The rhythmic expansion and recoil of arteries with each heartbeat, reflecting the heart rate and force of contraction.

Question 5

define Pulse Deficit

Answer 5

The difference between the apical pulse (heard directly over the heart) and the radial pulse (felt at the wrist); indicates inefficient heart contractions where not all beats generate a palpable pulse.

Question 6

define Blood Pressure

Answer 6

The force exerted by circulating blood on the walls of blood vessels, typically measured in the arteries as systolic over diastolic pressure (e.g., 120/80 mmHg).

Question 7

Sounds of Korotkoff

Answer 7

Used to identify systolic (first sound) and diastolic (last sound) pressures when taking manual blood pressure.

• Heard during blood pressure measurement with a sphygmomanometer and stethoscope
• Cuff is inflated above systolic pressure → no sound (artery is occluded)
• As cuff pressure drops below systolic pressure, blood begins to spurt through artery → first sound = systolic pressure
• Sounds become louder, then muffled
• When cuff pressure falls below diastolic pressure, blood flows freely → sounds disappear = diastolic pressure

Question 8

Diastole

Answer 8

• Ventricular relaxation phase
• Ventricles fill with blood from atria
• Corresponds to low arterial pressure (diastolic BP)

Question 9

Dicrotic Notch

Answer 9

• Small dip in aortic pressure tracing (arterial pressure)
• Occurs after aortic sumilunar valve closes
• Represents elastic recoil of aorta and brief backflow -> cardiac circulation

Question 10

S1 / S2

Answer 10

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

Question 11

Pulse presure

Answer 11

• Difference between systolic and diastolic pressure
• Formula: PP = SBP − DBP
• Reflects stroke volume and arterial compliance

Question 12

Blood Pressure Definitions and Interpretation

Answer 12

Question 13

Answer 13

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)

Question 14

Answer 14

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

Question 15

Answer 15

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)

Question 16

Answer 16

axillary lymph nodes

• Located in the armpit (axilla)
• Drain upper limbs, breast, and thoracic wall
• Important in breast cancer metastasis

Question 17

Answer 17

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)

Question 18

Answer 18

inguinal lymph nodes

Question 19

#1

Answer 19

pharyngeal tonsils
unpaired tonsil

• 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

Question 20

#2

Answer 20

Palatine tonsils
paired 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

Question 21

#3

Answer 21

Lingual tonsils
paired 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

Question 22

Lymphatic vessel

Answer 22

thin-walled tubes, similar to blood vessels, that form a network throughout the body to collect and transport lymph fluid

Question 23

Answer 23

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

Question 24

Answer 24

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

Question 25

Answer 25

**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

Question 26

Answer 26

**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

Question 27

Answer 27

**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

Question 28

Answer 28

**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**

Question 29

Answer 29

**Lymph Node Histology** - **Lymph Node**: small, encapsulated structure that filters lymph - **Capsule**: dense connective tissue covering the node; sends inward trabeculae - **Cortex**: outer region beneath capsule; contains **lymphoid follicles** - **Lymphoid follicle**: dense spherical collections of B cells (may contain germinal centers) - **Medulla**: inner region; contains **medullary sinuses** and cords - **Medullary sinuses**: channels that carry filtered lymph toward the efferent lymphatic vesse

Question 30

Answer 30

**Lymph Node Histology** - **Capsule**: outer connective tissue layer; sends **trabeculae** inward - **Cortex**: contains **lymphoid follicles** (mostly **B cells**) with germinal centers for **B cell activation** - **Medulla**: inner region with **medullary cords** (lymphocytes + plasma cells) and **medullary sinuses** (drain lymph toward hilum)

Question 31

Answer 31

**Tonsil Histology** - **Crypts**: deep epithelial invaginations that **trap antigens** from food and air - **Lymphoid follicles**: located around crypts, contain **B cells** for **antibody production** - Function: initiate **immune response** to inhaled or ingested pathogens

Question 32

Answer 32

**Lymph Valve**

Question 33

**Pressure Changes: Atria vs. Ventricles**

Answer 33

- Atria contract first → **atrial pressure briefly rises** - Ventricles then contract → **ventricular pressure exceeds atrial pressure** → AV valves close - As **ventricular pressure exceeds aortic/pulmonary pressure**, SL valves open - During ventricular relaxation → **pressure drops** → SL valves close when pressure falls below aortic/pulmonary - When ventricular pressure falls below atrial pressure → **AV valves reopen**

Question 34

**Valve Closure Timing**

Answer 34

- **AV valves (mitral/tricuspid)** close when: - Ventricular pressure **> atrial pressure** (start of ventricular systole) - Heard as **"lub" (S1)** - **SL valves (aortic/pulmonary)** close when: - Arterial pressure **> ventricular pressure** (start of ventricular diastole) - Heard as **"dub" (S2)**

Question 35

**Clinical Significance of Heart Sounds & Murmurs**

Answer 35

*Normal Heart Sounds* - **S1 ("lub")**: AV valve closure (start of systole) - **S2 ("dub")**: SL valve closure (start of diastole) → Used to time cardiac cycle and assess valve function *Abnormal Heart Sounds* - **S3**: early diastole → may indicate **volume overload** (e.g., heart failure) - **S4**: late diastole → associated with **stiff ventricle** (e.g., hypertrophy) *Heart Murmurs* - Turbulent blood flow through valves - May indicate **valve stenosis** (narrowing) or **regurgitation** (backflow) - Graded by intensity and timing (systolic vs. diastolic) → Can signal **valvular disease**, **septal defects**, or **congenital abnormalities**

Question 36

**Thoracic Auscultation Sites for S1 and S2**

Answer 36

*S1 ("lub")* → best heard at **apex** - **Mitral valve**: 5th intercostal space, **midclavicular line** - **Tricuspid valve**: 4th intercostal space, **left sternal border** *S2 ("dub")* → best heard at **base** - **Aortic valve**: 2nd intercostal space, **right sternal border** - **Pulmonary valve**: 2nd intercostal space, **left sternal border** *Mnemonic*: **"All Physicians Take Money"** - Aortic → Pulmonic → Tricuspid → Mitral (in a clockwise pattern starting at top right)