There are five layers of the epidermis. From surface to base, the layers are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum and stratum basalis.

The stratum corneum is composed of several layers of barrier cells and serves mostly for protection. The stratum lucidum is only found in the palms and soles and helps thicken the skin. The stratum granulosum contains lipids and fatty acids. The stratum spinosum contains some immune cells, as well as lipids. The stratum basalis contains melanocytes and mechanoreceptor cells attached to the basement membrane.

The common bile duct stems from the joining of the common hepatic duct and the cystic duct. The common hepatic duct comes from the left and right hepatic ducts and lobes of the liver. The cystic duct comes from the gall bladder. These two ducts become the common bile duct which drains into the duodenum.

The skin is made up of two major components: the superficial epidermis layer and the deep dermis layer. The epidermis is essentially made up of four layers, however, there is an additional layer found in regions of thick skin. The four principle epidermal layers, going from superficial to deep, are the stratum corneum, stratum granulosum, stratum spinosum, and stratum basale. In regions of thick skin (namely the soles of the feet and palms of the hands) there is an additional layer of cells located between the stratum corneum and stratum granulosum, known as the stratum lucidum, which serves to enhance protection and cushioning of these areas.

The diaphragm has 3 main hiatuses – The first is at T8 through which the IVC passes through.The second is at T10 through which the esophagus and vagus nerve pass and the final hiatus is at T12 through which the Aorta, azygous vein and the thoraci lymphatic duct. A helpful mneumonic for this is I ATE (8), TEN EGGS At 12. I is for IVC with the ATE representing T8. The TEN for T10 and the EGGS stand for Esophagus, two g's for the two vaGus and the At for Aorta, which passes through the diaphragm at T12.

The heart is the pump that distributes oxygenated blood throughout the body and is enclosed in a sac known as the pericardium. The pericardial sac is made of the fibrous and serous pericardium. The heart has four chambers, which are divided by septums to prevent exchange of blood between adjacent chambers. The chambers of the heart are the right atrium, right ventricle, left artium, and left ventricle. The right atrium receives blood from the superior and inferior vena cavae. Blood then passes from the right atrium to the reight ventrical via the tricuspid valve. The right ventricle pumps blood into the pulmonary arteries for transport tot he lungs to receive oxygen. Following gas exchange, the pulmonary veins return the blood to the left atrium of the heart. The blood them passes through the bicuspid (mitral) valve before entering the left ventricle. The left ventricle pumps the blood into the aorta to be carried through arteries to the tissues of the body.

The diaphragm has 3 main hiatuses – The first is at T8 through which the IVC passes through.The second is at T10 through which the esophagus and vagus nerve pass and the final hiatus is at T12 through which the Aorta, azygous vein and the thoraci lymphatic duct. A helpful mneumonic for this is I ATE (8), TEN EGGS At 12. I is for IVC with the ATE representing T8. The TEN for T10 and the EGGS stand for Esophagus, two g's for the two vaGus and the At for Aorta, which passes through the diaphragm at T12.

Holocrine glands are exocrine glands that involve the rupture of the plasma membrane. In doing so, it involves the destruction of the cell. Apocrine glands only involve the shedding of the cytoplasm.

A hair has two principle parts: the shaft and the root. The shaft is seen above the skin and the root stays deep within the skin surface. The shaft and the root are made of keratinized epithelial cells, which have ceased to divide and are considered non-living. The cells of the hair are organized into three layers. The cuticle is the outermost layer, which wraps around the hair exterior. The next layer is the cortex, which surrounds the innermost layer, the medulla. The root sheath structure is separate from the actual hair and is constructed from living epithelial cells that anchor and nourish the hair.

B-lymphocytes mature in the bone marrow. They can also be created and matured in the liver. Both types of lymphocyte originate from stem cells in the bone marrow, but differ in their site of maturation.

T-lymphocytes mature in the thymus, where they interact with "self antigens." This process ensures that T-lymphocytes do not interact with antigens found in the body. If the immature cell interacts with self antigens, the T-lymphocyte will be destroyed. Mature T-lymphocytes that still react to self antigens can cause allergic reactions and autoimmune disease.

Mature lymphocytes are most commonly found in the lymph nodes, where they screen the plasma and fluids for antigens.

The skin consists of two main layers, the epidermis (outer layer) and the dermis (inner layer). The epidermis layer has several layers (strata) that contain four cell or five cell types, in thin and thick skin, respectively. Keratinocytes produce keratin, a protein that gives strength and flexibility to the skin and waterproofs the skin surface. Melanocytes produce melanin, the dark pigment that gives skin color and absorbs ultraviolet radiation to avoid damage to the DNA. Merkel's cells are involved in touch reception. Langerhans' cells help the immune system by processing foreign bodies.