HESI Entrance Exam Study guide Questions and Answers

HESI Entrance Exam Study guide Questions and Answers body planes imaginary lines used for reference; they include the median plane, the coronal plane, and the transverse plane. Median Plane divides the body into right and left halves. Also called the midsagittal plane. Planes of the Body ... Coronal Plane divides the body into front and rear sections. Also called the frontal plane. Frontal plane divides the body into front and rear sections. Also called the coronal plane. Horizontal Plane divides the body into a superior (or upper) and an inferior (or lower) section. Also called the transverse plane. Median Plane divides the body into right and left halves. Also called the midsagittal plane. Midsagittal Plane divides the body into right and left halves. Also called the median plane. Transverse Plane divides the body into a superior (or upper) and an inferior (or lower) section. Also called the horizontal plane. Direction and Location ... Anterior front side of the body, also known as ventral. Caudal in quadrapeds, the tail end [see inferior]. Cranial above or near the head, also known as superior. Distal farthest end from the trunk or head. Dorsal back side of the body, also known as the posterior. Inferior below also, toward the feet. Infra- prefix meaning below or under. Lateral away from the midline. Medial toward the midline. Posterior back side of the body, also known as the dorsal. Proximal closest part nearest the trunk or head. Superior above or near the head, also known as cranial. Supra- prefix meaning above or over. Ventral front side of the body, also known as anterior. Parts of the Human Skull ... Calvarium includes the brain case. Cranium includes the face and the calvarium. Mandible the lower jaw. Skull includes both the cranium and mandible. Bones of the Skull ... Ethmoid bone sieve-like spongy bone located in the anterior part of the floor of the cranium between the orbits. The ethmoid is the principal supporting structure of the nasal cavity. Frontal bone forms the forehead, the roofs of the orbits, and most of the anterior part of the cranial floor. Inferior Nasal Conchae one of three scroll-like bones that project from the lateral wall of the nasal cavity. The inferior nasal conchae articulate with the ethmoid, maxilla, lacrimal and paltine bones and form the lower part of the lateral wall of the nasal cavity. Lacrimal bone a thin scalelike bone, roughly resembling a fingernail in size and shape, at the anterior part of the medial wall of the orbit, articulating with the frontal and ethmoidal bones and the maxilla and inferior nasal concha. The lacrimal bone, the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Mandible the bone forming the lower jaw; the largest and strongest bone of the face, presenting a body and a pair of rami, which articulate with the skull at the tempromandibular joints. Maxillae paired bones uniting to form the upper jawbone. The maxillae articulate with every bone of the face except the mandible, or lower jawbone. The maxilla (plural: maxillae), also known as the mustache bone, is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible (lower jaw), which is also a fusion of two halves at the mental symphysis. Sometimes (e.g. in bony fish), the maxilla is sometimes called "upper maxilla", with the mandible being the "lower maxilla". Conversely, in birds the upper jaw is often called "upper mandible". Nasal bone small oblong bones that meet at the middle and superior part of the face. Their fusion forms the superior part of the bridge of the nose. Occipital bone a single trapezoid-shaped bone situated at the posterior and inferior part of the cranium. The occipital bone forms the back part of the skull and the base of the cranium. It joins with the parietal and temporal bones. In the center, underside (inferior) portion of the cranium, there is a large opening called the foramen magnum (fig. 3-5), through which nerve fibers from the brain pass and enter into the spinal cord. Figure 3-4.—Temporal bone. 3-2 Palatine bone a bone of extremely irregular form on each side of the skull that is situated in the posterior part of the nasal cavity between the maxilla and the pterygoid process of the sphenoid bone and that consists of a horizontal plate which joins the bone of the opposite side and forms the back part of the hard palate and a vertical plate which is extended into three processes and helps to form the floor of the orbit, the outer wall of the nasal cavity, and several adjoining parts called also palate bone palatine. One of two irregularly shaped bones (L-shaped) forming the posterior part of the hard palate, the lateral wall of the nasal fossa between the medial pterygoid plate and the maxilla, and the posterior part of the floor of the orbit. The posterior part of the hard palate, which separates the nasal cavity from the oral cavity, is formed by the horizontal plates. Vomer a roughly triangular bone that forms the inferior and posterior of the nasal septum. The vomer is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. Parietal bones one of the two quadrilateral bones on either side of the cranium forming part of the superior and lateral surfaces of the skull, and joining each other in the midline at the sagittal suture. The parietal bones form the greater portion of the sides and roof of the cranial cavity. Sphenoid bone The sphenoid bone (from Greek sphenoeides, "wedgelike") is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit. Its shape somewhat resembles that of a butterfly or bat with its wings extended. A single, irregular, wedge-shaped bone at the base of the skull, which forms a part of the floor of the anterior, middle, and posterior cranial fossae. This bone is referred to as the keystone of the cranial floor because it articulates with all the other cranial bones. Temporal bone one of the two irregular bones on either side of the skull forming part of the lateral surfaces and base of the skull, and containing the organs of hearing. The temporal bones form the inferior sides of the cranium and part of the cranial floor. The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum. The temporal bone supports that part of the face known as the temple. Zygomatic bone the triangular bones on either side of the face below the eyes, commonly referred to as the cheekbones, they form the prominences of the cheeks and part of the outer wall and floor of the orbits. It is situated at the upper and lateral part of the face and forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal and infratemporal fossae [Fig. 1]. It presents a malar and a temporal surface; four processes, the frontosphenoidal, orbital, maxillary, and temporal; and four borders. Bone Morphology ... Crest a narrow prominent ridge. Condyle a smooth rounded projection for articulation with another bone. Epiphysis the end of a long bone that is originally separated from the main bone by a layer of cartilage but that later becomes united to the main bone through ossification [compare to suture and symphysis]. The epiphysis is the rounded end of a long bone, at its joint with adjacent bone(s). Between the epiphysis and diaphysis (the long midsection of the long bone) lies the metaphysis, including the epiphyseal plate (growth plate). At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal plate, known as subchondral bone (see Wiktionary:subchondral). The epiphysis is filled with red bone marrow, which produces erythrocytes (red blood cells). Foramen a true hole in the bone [e.g. foramen magnum, incisive foramen. Foramen: A natural opening. Although a foramen is usually through bone, it can be an opening through other types of tissue, as with the foramen ovale in the heart. The plural of foramen is foramina. Line a narrow raised ridge. Meatus a small tubular opening. In anatomy, a meatus is a natural body opening or canal (Latin, 4th declension pl. meatus, or meatuses - often incorrectly meati). Examples include: the external acoustic meatus, the opening of the ear canal The internal auditory meatus, a canal in the temporal bone of the skull the urinary meatus, which is the opening of the urethra, situated on the glans penis in males, and in the vulva in females the superior meatus, middle meatus and inferior meatus of the nose Sulcus a groove. In neuroanatomy, a sulcus (Latin: "furrow", pl. sulci) is a depression or fissure in the surface of the brain. It surrounds the gyri, creating the characteristic appearance of the brain in humans and other large mammals. Large furrows (sulci) that divide the brain into lobes are often called fissures. The large furrow that divides the two hemispheres—the interhemispheric fissure—is very rarely called a "sulcus". Suture the line formed by the junction of two bones or an immovable joint between two bones, especially of the skull [compare to epiphysis and symphysis]. Symphysis the line or junction formed by a cartilaginous articulation between two bones without an intervening synovial membrane, this articulation often fuses as in the two bones and the two halves of the mandibles [compare to suture and epiphysis]. Trochanter Trochanter: One of the bony prominences toward the near end of the thigh bone (the femur). There are two trochanters: •The greater trochanter: A powerful protrusion located at the proximal (near) and lateral (outside) part of the shaft of the femur; •The lesser trochanter: A pyramidal prominence projecting from the proximal (near) and medial (inside) part of the shaft of the femur. The greater trochanter is also called the major trochanter, the outer trochanter, and the lateral process of the femur. The lesser trochanter is alternatively called the minor trochanter, the inner trochanter and the medial process of the femur. The trochanters are points at which hip and thigh muscles attach. The greater trochanter gives attachment to a number of muscles (including the gluteus medius and minimus, piriformis, obturator internus and externus, and gemelli muscles) while the lesser trochanter receives the insertion of several muscles (including the psoas major and iliacus [iliopsoas] muscles). A large rounded projection for muscle attachment. Histology Terms ... adipose A loose connective tissue made up of specialized cells called adipocytes, which store triglycerides. Adipose tissue is a major reserve of body energy and supports and protects various organs. In histology, adipose tissue or body fat or just fat is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat; fat in its solitary state exists in the liver and muscles. Adipose tissue is derived from lipoblasts. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Obesity or being overweight in humans and most animals does not depend on body weight but on the amount of body fat—to be specific, adipose tissue. Two types of adipose tissue exist: white adipose tissue (WAT) and brown adipose tissue (BAT). Adipose tissue also serves as an important endocrine organ[1] by producing hormones such as leptin, resistin, and the cytokine TNFα. The formation of adipose tissue appears to be controlled by the adipose gene. Adipose tissue was first identified by the Swiss naturalist Conrad Gessner in 1551. anchoring junction a cellular junction which serves to anchor cells to one another or to extracellular material; seen in tissues subjected to friction and stretching (e.g., muscle tissue of heart). Bricks in a building must be stuck together and also tied somehow to the foundation. Similarly, cells within tissues and organs must be anchored to one another and attached to components of the extracellular matrix. Cells have developed several types of junctional complexes to serve these functions, and in each case, anchoring proteins extend through the plasma membrane to link cytoskeletal proteins in one cell to cytoskeletal proteins in neighboring cells as well as to proteins in the extracellular matrix. Three types of anchoring junctions are observed, and differ from one another in the cytoskeletal protein anchor as well as the transmembrane linker protein that extends through the membrane: apical surface The free or unattached surface of an epithelial cell. Epithelia are sheets of cells that provide the interface between masses of cells and a cavity or space (a lumen). •The portion of the cell exposed to the lumen is called its apical surface. •The rest of the cell (i.e., its sides and base) make up the basolateral surface. Tight junctions seal adjacent epithelial cells in a narrow band just beneath their apical surface. Tight junctions perform two vital functions: •They prevent the passage of molecules and ions through the space between cells. So materials must actually enter the cells (by diffusion or active transport) in order to pass through the tissue. This pathway provides control over what substances are allowed through. •They block the movement of integral membrane proteins (red and green ovals) between the apical and basolateral surfaces of the cell. Thus the special functions of each surface, for example ◦receptor-mediated endocytosis at the apical surface ◦exocytosis at the basolateral surface can be preserved. apocrine An exocrine gland which accumulates its secretory product at the apical surface of each cell. That part of each cell then separates from the remainder to from a secretion in the lumen of the gland. The cells then repair themselves (e.g., mammary glands). Apocrine is a term used to classify exocrine glands in the study of histology. Cells which are classified as apocrine bud their secretions off through the plasma membrane producing membrane bound vesicles in the lumen. Apocrine glands are a type of human sweat gland that are present in areas such as the axillae (armpits), areola, in the perineum (genital areas), around the belly button and in the external auditory canal(as wax-secreting glands). Specialized types of apocrine glands present on the eyelids are called Moll's glands. Apocrine sweat glands are inactive until they are stimulated by hormonal changes in puberty. Apocrine glands secrete a milky, viscous odourless fluid which only develops a strong odour when it comes into contact with bacteria on the skin surface. Apocrine glands secrete this fluid by a method called decapitation secretion. That is, the apical portion of the secretory cell of the gland pinches off and enters the lumen of the gland. In contrast to this mechanism of secretion, Eccrine glands secrete by a method called merocrine secretion and sebaceous glands secrete by a method called holocrine secretion. Apocrine sweat glands are mainly thought to function as olfactory pheremones, chemicals important in attracting a potential mate. areolar a widely distributed connective tissue made up of a number of different types of cells; combines with adipose tissue to form the subcutaneous layer of the body. Areolar tissue exhibits interlacing,[1] loosely organized fibers,[2] abundant blood vessels, and significant empty space. Its fiber run in random directions and are mostly collagenous, but elastic and reticular fibers are also present. Areolar tissue is highly variable in appearance. In many serous membranes, it appears as a loose arrangement of collagenous and elastic fibers, scattered cells of various types; abundant ground substance; numerous blood vessels. In the skin and mucous membranes, it is more compact and sometimes difficult to distinguish from dense irregular connective tissue. It is the most widely distributed connective tissue type in vertebrates. It is sometimes equated with "loose connective tissue".[3] In other cases, "loose connective tissue" is considered a parent category that includes mucous connective tissue, reticular connective tissue and adipose tissue. basal lamina the more superficial of two layers (along with the reticular lamina) making up the basement membrane. It is produced by the overlying epithelial tissue. 1 : the part of the gray matter of the embryonic neural tube from which the motor nerve roots arise 2 : a thin extracellular layer composed chiefly of collagen, proteoglycans, and glycoproteins (as laminin and fibronectin) that lies adjacent to the basal surface of epithelial cells or surrounds individual muscle, fat, and Schwann cells and that separates these cells from underlying or surrounding connective tissue or adjacent cells basal surface the surface of an epithelial cell which is attached to the underlying basement membrane. basement membrane the thin extracellular layer which attaches the epithelium to the underlying connective tissue. It is made up of a superficial basal lamina and an underlying reticular lamina. -blast a suffix which denotes a less differentiated precursor cell. It may or may not retain mitotic capability. Examples: myeloblast (white cell precursor), osteoblast (bone cell precursor). cilia hairlike projections of lining epithelial cells which help move substances through the lumen by a coordinated waving motion. collagen A protein which is the main component of connective tissue. Collagen is a group of naturally occurring proteins. In nature, it is found exclusively in animals.[1][clarification needed] It is the main protein of connective tissue. It is the most abundant protein in mammals,[2] making up about 25% to 35% of the whole-body protein content. In muscle tissue it serves as a major component of endomysium. Collagen constitutes 1% to 2% of muscle tissue, and accounts for 6% of the weight of strong, tendinous muscles.[3] Gelatin, which is used in food and industry, is derived from collagen. collagen fiber The most common of three types of fiber embedded in the matrix between cells of connective tissue. These lie in parallel rows, and add great strength. Collagen fibers are an essential component of the body as it is a type of protein. Given below is some interesting information about these collagen fibers, so take a look. As it is well known, collagen fibers are naturally occurring proteins found exclusively in animals and they are the main proteins in the connective tissues. Collagen fiber is the most commonly found protein in mammals and it makes up 25 to 35% of the whole body protein. Since 1930s scientists have been performing active research on the conformation of the collagen monomer which is sheet like or microfibrillar. This monomeric structure of the collagen fibers was described by Fraser, Miller and Wess with close observation. The collagen molecule is also called the 'tropocollagen' and is a aggregate of larger collagen fibrils. Given below is a detailed description about collagen fibers and their function. Collagen Fiber Information Tropocollagen, is approximately 300 nm in length and 1.5 nm in diameter. It is made up of polypeptide strands known as the alpha chains and each of them is a left handed helix in conformation. There are three such left handed helices which are twisted together to form a right handed triple helix or super helix which are bonded to each other with hydrogen bonds. This entire molecule which is collectively called the collagen fiber is made up of a regular arrangement of amino acids and hence it's called a protein. Read on for information about the formation, types and function of these collagen fibers. More on collagen injections. Collagen Fiber Types Collagen is found in many parts of the body but the most common is the collagen fibers connective tissue. Throughout the body th