Lab Practical 2 Study Guide: Blood Vessels, Circulation, and Lymphatic System

Lab Practical 2 Study Guide: Blood Vessels, Circulation, and Lymphatic System

Overview

This study guide outlines the essential topics and structures to review for Lab Practical 2 in Anatomy & Physiology. It covers identification of blood vessels, understanding vessel wall layers, blood pressure measurement, and key lymphatic organs and tissues.

Blood Vessels and Circulation

Types of Blood Vessels

Blood vessels are classified into three main types, each with distinct functions and structures:

• Arteries: Vessels that carry blood away from the heart. Most arteries carry oxygenated blood, except for the pulmonary arteries.

• Veins: Vessels that return blood to the heart. Most veins carry deoxygenated blood, except for the pulmonary veins.

• Capillaries: Microscopic vessels where exchange of gases, nutrients, and wastes occurs between blood and tissues.

Vessel Wall Layers

The walls of arteries and veins are composed of three layers:

• Tunica intima: The innermost layer, consisting of endothelium.

• Tunica media: The middle layer, made up of smooth muscle and elastic fibers; thicker in arteries.

• Tunica externa (adventitia): The outermost layer, composed of connective tissue.

Capillaries have only a single layer of endothelium to facilitate exchange.

Major Arteries and Veins to Identify

Be able to identify the following arteries and veins on models or diagrams. For arteries, know the body structures they supply; for veins, know the structures they drain.

ARTERIES

VEINS

ascending aorta aortic arch brachiocephalic common carotid subclavian external carotid internal carotid axillary brachial ulnar radial DESCENDING AORTA thoracic aorta abdominal aorta celiac trunk superior mesenteric renal gonadal inferior mesenteric common iliac internal iliac external iliac femoral popliteal anterior and posterior tibial CIRCLE OF WILLIS internal carotid anterior cerebral posterior communicating basilar posterior cerebral

superior vena cava azygos brachiocephalic internal jugular subclavian axillary brachial cephalic ulnar radial inferior vena cava hepatic gonadal renal suprarenal common iliac internal iliac external iliac femoral popliteal anterior & posterior tibial HEPATIC (VENOUS) CIRCULATION hepatic portal inferior mesenteric splenic superior mesenteric gastric pulmonary arteries jugular veins pulmonary veins

Circle of Willis

The Circle of Willis is a circular arterial structure at the base of the brain that provides collateral blood flow between the anterior and posterior cerebral circulations. Key arteries include:

• Internal carotid arteries

• Anterior cerebral arteries

• Posterior communicating arteries

• Basilar artery

• Posterior cerebral arteries

Hepatic Portal Circulation

The hepatic portal system carries blood from the digestive organs to the liver for processing before it enters the systemic circulation. Major veins include:

• Hepatic portal vein

• Splenic vein

• Superior mesenteric vein

• Inferior mesenteric vein

• Gastric veins

Blood Pressure Measurement

Principles and Procedure

• Blood pressure is the force exerted by circulating blood on the walls of blood vessels.

• Measured using a sphygmomanometer and stethoscope, typically at the brachial artery.

• Two values are recorded: systolic (pressure during heart contraction) and diastolic (pressure during heart relaxation).

Why measure blood pressure? It is a key indicator of cardiovascular health and can help diagnose hypertension or hypotension.

Lymphatic System

Major Lymphatic Organs

• Thymus: Site of T lymphocyte maturation; located in the mediastinum.

• Tonsils: Lymphatic tissue in the pharynx; first line of defense against ingested or inhaled pathogens.

• Spleen: Filters blood, recycles old red blood cells, and stores white blood cells and platelets.

Lymphatic Vessels and Drainage

• Lymphatic vessels transport lymph from tissues to the venous system.

• Cisterna chyli: A dilated sac at the lower end of the thoracic duct; collects lymph from the lower limbs and intestines.

• Trunks and ducts: Major lymphatic vessels that drain specific body regions.

Be able to identify the body regions drained by each lymphatic trunk on diagrams.

Histology of Lymphatic Organs

• Lymph nodes: Identify capsule, trabeculae, cortex, medulla, medullary cords, lymph nodules (follicles) with germinal centers.

• Spleen: Identify white pulp (lymphatic tissue) and red pulp (blood-filled sinuses).

• Tonsils: Identify nodules (follicles) and crypts.

Summary Table: Key Structures to Identify

Structure	Key Features to Identify
Arteries & Veins	Name, location, whether they supply or drain specific organs/regions
Vessel Wall Layers	Tunica intima, tunica media, tunica externa
Circle of Willis	Arterial circle at base of brain; collateral circulation
Hepatic Portal System	Veins draining digestive organs to liver
Lymphatic Organs	Thymus, tonsils, spleen; histological features
Lymphatic Vessels	Cisterna chyli, trunks, ducts; regions drained

Additional info:

• For exam preparation, practice identifying these structures on both models and histological slides.

• Review the function and clinical significance of each vessel and lymphatic organ.