The lunula is the white crescent shaped part of the fingernail. Sulci are grooves in gyri. The dermis is the innermost layer of skin. Finally, the tissue within the uterus is the endometrium, myometrium, and perimetrium.

The grey matter of the spinal cord contains the cell bodies of neurons. The white matter is composed of the axons of neurons. The axons of neurons in the spinal cord appear white because of the myelin sheath that is added by oligodendrocytes, which allows for faster conduction of action potentials via saltatory conduction. Erythrocytes are red blood cells and are not found in the spinal cord. Sulci are grooves between the gyri in the cerebrum. 

The cochlea is a fluid-filled structure that converts sound waves to nerve signals that can be sent to the brain. The eardrum is a structure that detects sound waves, which cause it to vibrate. The middle ear is the air filled cavity that is crossed by the ossicles. The semicircular canals are fluid filled structures that detect head movement and position.

The ampulla is a part of the semicircular duct that contains delicate structures that detect movement, particularly rotation. The cochlear duct is a structure that is coiled like a snail's shell and contains structures that can convert sound waves to nerve signals. The saccule is a structure that carries info about the head position and movement to the brain. Ossicles are the small bones in the ear canal that transmit and amplify vibrations of the eardrum.

The correct order of the ossicles from most distal to most proximal is malleus, incus, stapes. The malleus is also known as the hammer. The incus is also known as the anvil. The stapes is also known as the stirrup.

The alar cartilage is the cartilage that gives shape and flexibility around the nostrils. The septal nasal is the cartilage that divides the nasal cavity in half. Fibrofatty tissue provides support around the nostrils. The nasal bones give support and shape near the root of the nose. 

The other name for the eardrum is the tympanic membrane. The temporal bone is a bone of the skull. The ossicles are the three tiny bones that transmit and amplify the movements of the inner ear. The semicircular canals are fluid-filled structures that detect head movements and position.

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.

Oxygen-rich blood returns from the lungs via the pulmonary veins. It first passes through the left atrium and then the mitral valve into the left ventricle. Arteries almost always carry oxygen-rich blood away from the heart, but the pulmonary arteries uniquely carry oxygen-poor blood from the right ventricle to the lungs to be oxygenated. The superior vena cava drains oxygen-poor blood from the neck and upper body into the right atrium. The tricuspid valve separates the right ventricle and atrium and prevents back flow between these two chambers. The aortic valve prevents back flow of oxygen-rich blood into the left ventricle. Out of the structures listed it is the mitral valve that first is touched by oxygen-rich blood.

The ileum makes up the distal three-fifths of the small intestine. Compared to the jejunum, the ileum has more mesenteric fat, more arterial arcades, a shorter vasa recta, thinner walls, and fewer and less prominent plicae circulares or mucosal folds.