Laszlo Vass, Ed.D. Version 42-0008-01-01
Please explain the purpose of this lab. Include in your explanation the major concepts you learned and any safety concerns associated with the lab. Purpose is to understand how the veins and arteries run through the body and how they function while the heart beats, where they deliver and drain blood to/from and how the cardiovascular system works together. Lock up the dogs while dissecting. wear face mask to protect from smells and splatter. take caution using sharp objects. do not be distracted.
Exercise 1: Microscopic Structure of Blood Vessels Observations Sketch your slide in the space below and label the structures indicated in the procedure. Be sureto include a description of the structures you observed on the slide
A. Describe the three layers of the wall of an artery.
Tunica Externa (adventitia): strong outer covering (also found in veins). It is composed of elastic fibers, collagen and connective tissue. This layer allows for stretch and prevents overexpansion of the artery wall from blood flow and pressure.
Tunica Media: Smooth muscle, elastic fibers. They are thicker in arteries than in veins to prevent a rupture in the artery. Vasomotion (change in the diameter of the blood vessels.
Tunica Interna (Intima): Inner layers of elastic membrane lining and smooth simple squamous called endothelium. This layer is exposed to blood and secretes a chemical that stimulates dilation or constriction of the vessel. Also helps repel platelets and blood so they do not stick to the walls--->>> Thrombus or clotting--->>>Can also occur if damage happens to endothelium. This layer is also selectively permeable.
B. How do arterial walls differ from venous walls? There are 3 class sizes of arteries vs veins. Also the resistance of the vessel walls. Arteries are extremely strong resilient tissue structure because of the way the heart beats. Each beat creates a surge of pressure so they must be more muscular and allow for stretch than veins.
C. What is the function of valves in the peripheral veins? Allows for blood to flow upward against gravity towards the heart. It prevents improper downward flow which can lead to varicose veins.
D. Why are arteries deeper than veins in the body? There is a great pressure of flow through the arteries and in order to keep them protected they need to be deeper into the body than the veins. If they arteries were vulnerable and became punctured they artery would allow a faster flow of blood out of the body causing the person to lose blood very quickly. It would be life threatening. Blood flow through the veins is slower so damage to the veins are much easier to repair/heal. Arteries need to be able to withstand the high pressure to reach vital organs.
Exercise 2: Identifying the Major Arteries and Veins
on a Cat
A. From the aortic arch to the superior vena cava, list the major arteries and veins that deliver and drain blood from the head of the cat. RIGHT COMMON CAROTID ARTERY, LEFT EXTERNAL CAROTID, LEFT INTERNAL CAROTID, LEFT LARYNGEAL, LEFT SUPERIOR THYROID, LEFT COMMON CAROTID ARTERY. INTERNAL/EXTERNAL JUGULAR VEIN, SUBCLAVICAL VEIN, BRACHIOCEPHALIC.
B. Name the blood vessels that deliver and drain blood to and from the heart. AORTA, PULMONARY TRUNK, ARTERIAL DUCT, PULMONARY ARTERIES. VEINS= SUPERIOR/INFERIOR VENA CAVA
C. Describe the branching of the aorta as it leaves the heart. Where does it go? 1. CAROTID ARTERIES (HEAD AND NECK), 2. CORONARY ARTERIES (SUPPLY BLOOD TO THE HEART), 3. HEPATIC (LIVER), 4. MESENTERIC (INTESTINES), 5. RENAL (KIDNEYS), 6. FEMORAL (LEGS)
D. Name the major arteries and veins that deliver and drain blood to and from the upper appendages.
Right Side of the Body: subclavical (shoulder area), Axillary (arm), Brachial (above elbow),...