Abdomen

Portion of the body between the thorax and the pelvis.

Abdominal cavity

Space containing the stomach, intestines, kidneys, liver, gallbladder, pancreas, spleen, and ureters.

Acetabulum

Large socket in the pelvic bone for the head of the femur.

Acromion

Extension of the scapula, which forms the high point of the shoulder.

Adenoids

Lymphoid tissue located behind the nasal cavity.

Adrenal glands, suprarenals

Paired glands, one of which is located above each kidney.  The outer portion is called the adrenal cortex, and the inner portion is called the adrenal medulla.  The hormones are secreted by the adrenal glands: growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropic hormones (follicle-stimulating hormone, luteinizing hormone, prolactin or lactogenic hormone), posterior lobe or neurohypophysis (antidiuretic hormone, oxytocin).

Adrenocorticotropic hormone (ACTH)

Stimulates the adrenal cortex.

Aldosterone

Secreted by the cortex.  Electrolytes (mineral salts) that are necessary for normal body function are regulated by this hormone.

Alveolus (pl. Alveoli)

Air sacs at the end of the bronchioles.  Oxygen and carbon dioxide are exchanged through the alveolar walls and the capillaries.

Amnion

Innermost layer of the fetal membrane.

Amniotic fluid

Fluid within the amniotic sac, which surrounds the fetus.

Amniotic sac

Membranous bag that surrounds the fetus.

Anterior lobe or adenohypophysis

Produces and secretes hormones: growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropic hormones (follicle-stimulating hormone, luteinizing hormone), prolactin or lactogenic hormone.

Antidiuretic hormone (ADH)

Stimulates the kidney to reabsorb water.

Antrum

Portion of the pylorus that connects to the body of the stomach.

Anus

Sphincter muscle (ring-like band of muscle fiber that keeps an opening tight) at the end of the digestive tract.

Aorta

Largest artery in the body, originating at the left ventricle and descending through the thorax and abdomen.

Aponeurosis

Strong sheet of tissue that acts as a tendon to attach muscles to bone.

Appendix

Small pouch, which has no function in digestion, attached to the cecum.

Aqueous humor

Watery liquid found in the anterior cavity of the eye.

Arachnoid

Delicate middle layer of the meninges.  The arachnoid membrane is loosely attached to the pia mater by web-like fibers, which allow for the subarachnoid space.

Areola

Pigmented area around the breast nipple.

Arteries

Blood vessels that carry blood away from the heart.  All arteries, with the exception of the pulmonary artery, carry oxygen and other nutrients from the heart to the body cells.  The pulmonary artery, in contrast, carries carbon dioxide and other waste products from the heart to the lungs.

Arterioles

Smallest arteries.

Articular cartilage

Smooth layer of gristle covering the contacting surface of joints.

Auricle (pinna)

External structure located on both sides of the head.  The auricle directs sound waves into the external auditory meatus.

Bartholin glands

Pair of mucus-producing glands located on each side of the vagina and just above the vaginal opening.

Bicuspid valve

Located between the left atrium and left ventricle (also called mitral valve).

Bile ducts

Passageways that carry bile: the hepatic duct is a passageway for bile from the liver, and the cystic duct carries bile from the gallbladder.  They join to form the common bile duct, which conveys bile to the duodenum.

Blood

Composed of plasma and formed elements, such as erythrocytes, leukocytes, and thrombocytes (platelets).

Blood vessels

Tube-like structures that carry blood throughout the body.

Body

Central portion of the stomach.

Bone marrow

Material found in the cavities of bones

Brain

Major portion of the central nervous system.

Brainstem

Stem-like portion of the brain that connects with the spinal cord.  Then of the 12 cranial nerves originate in the brainstem.

Bronchioles

Smallest subdivision of the bronchial tree.

Bronchus (pl. Bronchi)

One of two branches form the trachea that conducts air into the lungs, where it divides and subdivides.  The branchings resemble a tree, therefore they are referred to as a bronchial tree.

Bursa (pl. Bursae)

Fluid-filled sac that allows for easy movement of one part of a joint over another.

Calcaneus

Heel bone.

Cancellous (spongy) bone

Contains little spaces like a sponge and is encased in the layers of compact bone.

Capillaries

Microscopic blood vessels that connect arterioles with venules.  Materials are passed between the blood and tissue through the capillary walls.

Cardia

Area around the opening of the esophagus.

Carpal bones

Wrist bones.

Cecum

Blind U-shaped pouch that is the first portion of the large intestine.

Cell

Basic unit of all living things.  The human body is composed of trillions of cells, which vary in size and shape according to function.

Cell membrane

Forms the boundary of the cell.

Cerebellum

Located under the posterior portion of the cerebrum.  Its function is to assist in the co-ordination of skeletal muscles and to maintain balance (also called hindbrain).

Cerebrospinal fluid

Clear, colorless fluid contained in the ventricles that flow through the subarachnoid space around the brain and spinal cord.  It cushions the brain and spinal cord from shock, transports nutrients, and clears metabolic waste.

Cerebrum

Largest portion of the brain, divided into left and right hemispheres.  The cerebrum controls the skeletal muscles, interprets general senses (such as temperature, pain, and touch), and contains centers for sight and hearing.  Intellect, memory, and emotional reactions also take place in the cerebrum.

Cervical vertebrae (C1 to C7)

First set of seven bones, forming the neck.

Cervix

Narrow lower portion of the uterus.

Chorion

Outermost layer of the fetal membrane.

Choroid

Middle layer of the eye, which is interlaced with many blood vessels.

Chromosomes

Located in the nucleus of the cell.  There are 46 chromosomes in all normal human cells, with the exception of mature sex cells, which have 23.

Clavicle

Collarbone.

Clitoris

Highly erogenous erectile body located anterior to the urethra.

Coccyx

Four vertebrae fused together to form the tailbone.

Cochlea

Is snail-shaped and contains the organ of hearing.  The cochlea connects to the oval window in the middle ear.

Colon

Next portion of the large intestine. Divided into four parts: ascending, transverse, descending and sigmoid colon.

Compact bone

Dense, hard layers of bone tissue that lie underneath the periosteum.

Conception, fertilization

Beginning of pregnancy, when the sperm enters the ovum (usually in the fallopian tube).

Conjunctiva

Mucous membrane lining the eyelids and covering the anterior portion of the sclera.

Connective tissue

Connects, supports, penetrates, and encases various body structures.  Adipose (fat) and osseous (bone) tissues and blood are types of connective tissue.

Cornea

Transparent anterior part of the sclera, which is in front of the aqueous humor and lies over the iris.

Corpus, or body

Large central portion of the uterus.

Cortisol

Secreted by the cortex.  It aids the body during stress by increasing glucose levels to provide energy (also called hydrocortisone).

Cranial cavity

Space inside the skull (cranium) containing the brain.

Cytoplasm

Gel-like fluid inside the cell.

Dermis

Inner layer of skin (also called the true skin).

Diaphragm

Muscular partition that separates the thoracic cavity from the abdominal cavity.  It aids in the breathing process.

Diaphysis

Shaft of the long bones.

DNA (deoxyribonucleic acid)

Comprises each gene; is a chemical that regulates the activity of the cell.

Duodenum

First 10 to 12” of the small intestine.

Dura mater

Tough outer layer of the meninges.

Embryo

Unborn offspring in the stage of development from implantation of the zygote to the second month of pregnancy.

Endocardium

Inner lining of the heart.

Endometrium

Inner lining of the uterus.

Endosteum

Membranous lining of the hollow cavity of the bone.

Epicardium

Also called parietal pericardium.  It lines the pericardial sac.

Epidermis

Outer layer of skin.

Epididymis

A coiled 20-foot (6-m) tube atop each of the testes that carries the mature sperm up to the vas deferens.

Epigastric region

Directly above the umbilical region.

Epiglottis

Flap of cartilage that automatically covers the opening of and keeps food from entering the larynx during swallowing.

Epinephrine (adrenaline), norepinephrine (noradrenaline)

Secreted by the medulla.  These hormones help the body to deal with stress by increasing the body pressure, heartbeat, and respirations.

Epiphysis (pl. Epiphyses)

Ends of the long bones.

Epithelial tissue

The major covering of the external surface of the body; forms membranes that line body cavities and organs and is the major tissue in glands.

Erythrocytes

Red blood cells that carry oxygen.

Esophagus

10” tube that extends from the pharynx to the stomach.

Eustachian tube

Connects the middle ear and the pharynx.  It equalizes air pressure on both sides of the eardrum.

External auditory meatus (canal)

Short tube that ends at the tympanic membrane.  The inner part lies within the temporal bone of the skull and contains the glands that secrete earwax (cerumen).

Fallopian, or uterine, tubes

Pair of 5-inch (12-cm) tubes, attached to the uterus, that provide a passageway for the ovum to move from the ovary to the uterus.

Femur

Upper leg bone.

Fetus

Unborn offspring from the second month of pregnancy to birth.

Fimbria (pl. Fimbriae)

Finger-like projection at the free end of the fallopian tube.

Follicle-stimulating hormone (FSH), luteinizing hormone (LH)

Regulate development, growth, and function of the ovaries and testes.

Frontal/coronal plane

Vertical field passing through the body from side to side, dividing the body into anterior and posterior portions.

Fundus

Rounded upper portion of the uterus.

Fundus

Uppermost domed portion of the stomach.

Gallbladder

Small, sac-like structure that stores bile.

Gamete

Mature sex cell; sperm or ovum.

Ganglion (pl. Ganglia)

Group of nerve cell bodies located outside the central nervous system.

Genes

Regions within the chromosome.  Each chromosome has several thousand genes that determine hereditary characteristics.

Genitalia (genitals)

Reproductive organs (male and female).

Gestation period

Duration of pregnancy.

Gestation, pregnancy

Development of new individual from conception to birth.

Glans penis

Enlarged tip on the end of the penis.

Glomerulus (pl. Glomeruli)

Cluster of capillaries at the entrance of the nephron.  The process of filtering the blood, thereby forming urine, begins here.

Gonadotropic hormones

Affect the male and female reproductive systems;

Graafian follicles

100,000 microscopic sacs that make up a large portion of the ovaries.  Each follicle contains an immature ovum.  Normally one graafian follicle develops to maturity monthly between puberty and menopause.  It moves to the surface of the ovary and releases the ovum, which passes into the fallopian tube.

Growth hormone (GH)

Regulates the growth of the body.

Hair

Compressed, keratinized cells that arise from hair follicles; the sacs that enclose the hair fibers.

Hard palate

Anterior portion, supported by bone.

Heart

Muscular organ the size of a fist, located behind the sternum (breast bone) and between the lungs.  The pumping action of the heart circulates blood throughout the body.  The heart consists of two upper chambers, right atrium (pl. Atria) and the left atrium, and two lower chambers, the right ventricle and the left ventricle.  Valves of the heart keep the blood flowing in one direction.  The cardiac septum separates the right and left sides of the heart.

Hilum

Indentation on the medial side of the kidney where the ureter leaves the kidney.

Humerus

Upper arm bone.

Hymen

Fold of membrane found near the opening of the vagina.

Hypochondriac regions

To the right and left of the epigastric region.

Hypogastric region

Directly below the umbilical region.

Hypothalamus

Located near the pituitary gland in the brain.  The hypothalamus secretes “releasing” hormone that functions to stimulate or inhibit the release of pituitary gland hormones.

Ileum

Third portion of the small intestine, approx. 11’ long, which connects with the large intestine.

Iliac regions

To the right and left of the hypogastric region.

Ilium

Upper, wing-shaped part on each side.

Implantation, nidation

Embedding of the zygote in the uterine lining (about 7 days after fertilization).

Intervertebral disk

Cartilaginous pad found between the vertebrae in the spine.

Iris

The pigmented muscular structure that allows light to pass through.

Ischium

Lower, rear portion on which one sits.

Islets of Langerhans

Clusters of endocrine tissue found throughout the pancreas, made up of different cell types that secrete various hormones, including insulin and glucagons.  Non-endocrine cells found throughout the pancreas perform non-endocrine functions such as digestion.

Jejunum

Second portion of the small intestine, approx. 8’ long.

Keratin

Horny, or cornified, layer composed of protein.  It is contained in the hair, skin, and nails.

Kidneys

Two bean-shaped organs located on each side of the vertebral column on the posterior wall of the abdominal cavity behind the parietal peritoneum.  Their function is to remove waste products from the blood and to aid in maintaining water and electrolyte balances.

Labyrinth (inner ear)

Bony spaces within the temporal bone of the skull.  It contains the cochlea, semicircular canals, and vestibule.

Lacrimal glands and ducts

Produce and drain tears.

Lamina (pl. Laminae)

Part of the vertebral arch.

Large intestine

Canal that is approx. 5’ long and extends from the ileum to the anus.

Larynx (voice box)

Location of the vocal cords.  Air enters from the pharynx.

Lens

Lies directly behind the pupil.  Its function is to focus and bend light.

Leukocytes

White blood cells that fight infection.

Ligament

Flexible, tough band of fibrous connective tissue that attaches one bone to another at a joint.

Liver

Produces bile (necessary for the digestion of fats). It performs many functions with digestion and metabolism.

Lumbar regions

To the right and left of the umbilical region.

Lumbar vertebrae (L1 to L5)

Third set of five larger vertebrae, which forms the inward curve of the spine.

Lungs

Two sponge-like organs in the thoracic cavity.  The right lung consists of three lobes, and the left lung has two lobes.

Lymph

Transparent, usually colourless, tissue fluid.

Lymph nodes

Small, spherical bodies made up of lymphoid tissue.  They are found singularly or may be grouped together.  Nodes act as filters in keeping substances such as bacteria from the blood.

Mammary glands, or breasts

Milk-producing glands of the female.  Each breast consists of 15-20 divisions, or lobes.

Mammary papilla

Breast nipple.

Mandible

Lower jawbone.

Mastoid bone and cells

Located in the skull bone behind the external auditory meatus.

Maxilla

Upper jawbone.

Mediastinum

Space between the lungs.  It contains the heart, esophagus, trachea, great blood vessels, and other structures.

Medulla oblongata

Located between the pons and the spinal cord.  It contains centers that control respiration, heart rate, and the muscles in the blood vessel walls, which assist in determining blood pressure.

Meibomian glands

Oil glands found in the upper and lower edges of the eyelids that help lubricate the eye.

Melanin

Color, or pigmentation, of the skin.

Meninges

Three layers of membrane that cover the brain and spinal cord.

Meniscus

Crescent-shaped cartilage found in the knee.

Metacarpal bones

Hand bones.

Metatarsal bones

Foot bones.

Midbrain

Most superior portion of the brainstem.

Midsagittal plane

Divides the body into right and left halves.

Mouth

Opening through which food passes; breaks food into small bits by mastication (chewing) and mixing with saliva.

Muscle tissue

Composed of cells that have a special ability to contract, usually producing movement.

Myocardium

Middle, thick, muscular layer.

Myometrium

Muscular middle layer of the uterus.

Nails

Originate in the epidermis.  Nails are found on the upper surface of the ends of the fingers and toes.  The white area at the base of the nail is called the lunnula, or moon.

Nasal septum

Partition separating the right and left nasal cavities.

Nephron

Urine-producing microscopic structure.  Approximately 1 million nephrons are located in each kidney.

Nerve

Cord-like structure that carries impulses from one part of the body to another.  There are 12 pairs of cranial nerves and 31 pairs of spinal nerves.

Nervous tissue

Found in the nerves, spinal cord, and brain.  It is responsible for coordinating and controlling body activities.

Nose

Lined with mucous membrane and fine hairs.  It acts as a filter to moisten and warm the entering air.

Nucleus

Largest structure within the cell, usually spherical and centrally located.  It contains chromosomes for cellular reproduction and is the control center of the cell.

Optic nerve

Carries visual impulses from the retina to the brain.

Organ

Two or more kinds of tissues that together perform special body functions.  For example, the skin is an organ composed of epithelial, connective, muscle, and nerve tissue.

Ossicles

Bones of the middle ear that carry sound vibrations.  The ossicles are composed of the malleus (hammer), incus (anvil), and stapes (stirrup).  The stapes connects to the oval window, which transmits the sound vibrations to the inner ear.

Ovaries

Pair of almond-shaped organs located in the pelvic cavity.  Egg cells are stored in the ovaries.

Ovulation

Expulsion of an ovum from the ovary.

Ovum (pl. Ova)

Female egg cell.

Oxytocin

Stimulates uterine contractions during labor and postpartum.

Palate

Separates the nasal cavity from the oral cavity.

Pancreas

Produces pancreatic juice, which helps digest all types of food and secretes insulin for carbohydrate metabolism.

Paranasal sinuses

Air cavities within the cranial bones that open into the nasal cavities.

Parathyroid glands

Four small bodies lying directly behind the thyroid.  Parathormone (PTH), the hormone produced by the glands, helps maintain the level of calcium in the blood.

Patella (pl. Patellae)

Kneecap.

Pelvic bone, hip bone

Made up of three bones fused together.

Pelvic cavity

Space containing the urinary bladder, certain reproductive organs, parts of the large intestine, and the rectum.

Penis

Male organ of urination and copulation (sexual intercourse).

Pericardium

Two-layer sac (pericardial sac) covering the heart (pericardial fluid allows the layers to move without friction).

Perimetrium

Outer thin layer that covers the surface of the uterus.

Perineum

Pelvic floor in both the male and female.  In females it usually refers to the area between the vaginal opening and the anus.

Periosteum

Outermost layer of the bone, made up of fibrous tissue.

Peritoneum

Serous sac lining the abdominal and pelvic cavities.

Phalanges (sing. Phalanx)

Finger and toe bones.

Pharynx (throat)

Serves as a food and air passageway.  Air enters from the nasal cavities and passes through the pharynx to the larynx.  Food enters the pharynx from the mouth and passes into the esophagus.

Pharynx (throat)

Performs the swallowing action that passes food from the mouth into the esophagus.

Pia mater

Thin inner layer of the meninges.

Pituitary gland, hypophysis cerebri

Approximately the size of a pea and located at the base of the brain.  The pituitary is divided into two lobes.

Placenta, afterbirth

Structure that grows on the wall of the uterus during pregnancy and allows for nourishment of the unborn child.

Plasma

Liquid portion of blood in which cells are suspended.

Platelets (thrombocytes)

One of the formed elements in the blood that is responsible for aiding in the clotting process.

Pleura

Serous membrane covering each lung and lining the thoracic cavity.

Pons

Literally means bridge.  It connects the cerebrum with the cerebellum and brainstem.

Prepuce

Fold of skin near the tip of the penis (foreskin of the penis).

Prolactin or lactogenic hormone (PRL)

Promotes development of glandular tissue during pregnancy and produces milk after birth of an infant.

Prostate gland

Encircles the upper end of the urethra.  The prostate gland secretes a fluid that aids in the movement of the sperm and ejaculation.

Pubic symphysis

Cartilaginous joint at which two pubic bones fuse together.

Pubis

Anterior portion of the pelvic bone.

Pupil

Opening in the center of the iris.

Pyloric sphincter

Ring of muscle that guards the opening between the stomach and the duodenum.

Pylorus

Lower part of the stomach that connects to the small intestine.

Rectouterine pouch

Pouch between the posterior wall of the uterus and the anterior wall of the rectum (also called Douglas cul-de-sac).

Rectum

Remaining portion of the large intestine, approx. 8 to 10” long extending from the sigmoid colon to the anus.

Red marrow

Thick, blood-like material found in flat bones and the ends of long bones.  Location of blood cell formation.

Renal pelvis

Funnel-shaped reservoir that collects the urine and passes it to the ureter.

Retina

Innermost layer of the eye, which contains the vision receptors.

Sacrum

Next five vertebrae, which fuse together to form a triangular bone positioned between the two hip bones.

Sagittal plane

Vertical field running through the body from front to back, dividing the body into right and left sides.

Salivary glands

Produce saliva, which flows into the mouth.

Scapula

Shoulder blade.

Sclera

Outer protective layer of the eye; the portion seen on the anterior portion of the eyeball is referred to as the white of the eye.

Scrotum

Sac suspended on both sides of and just behind the penis.  The testes are enclosed in the scrotum.

Sebaceous glands

Secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis.

Semen

Composed of sperm, seminal fluids, and other secretions.

Semicircular canals and vestibule

Contains receptors and endolymph that help the body maintain its sense of balance (equilibrium).

Semilunar valves

One is located between the right ventricle and the pulmonary artery and the other is between the left ventricle and the aorta.

Seminal vesicles

Two main glands located at the base of the bladder that open into the vas deferens.  The glands secrete a thick fluid, which forms part of the semen.

Seminiferous tubules

Up to 900 coiled tubes within the testes in which spermatogenesis occurs.

Small intestine

20’ canal extending from the pyloric sphincter to the large intestine.

Soft palate

Posterior portion, not supported by bone.

Sperm (spermatozoon, pl. Spermatozoa)

The microscopic male germ cell, which, when united with the ovum, produces a zygote (fertilized egg) that with subsequent development becomes an embryo.

Spinal cavity

Space inside the spinal column containing the spinal cord.

Spinal cord

Passes through the vertebral canal extending from the medulla oblongata to the level of the second lumbar vertebra.  The spinal cord conducts nerve impulses to and from the brain and initiates reflex action to sensory information without input from the brain.

Spleen

Located in the left side of the abdominal cavity between the stomach and the diaphragm.  In adulthood, the spleen is the largest lymphatic organ in the body.

Sternum

Breastbone.

Stomach

J-shaped sac mixes and stores food, secretes chemicals for digestion, and secretes hormones for local communication control.

Sudoriferous (sweat) glands

Tiny, coiled, tubular structures that emerge through pores on the skin's surface and secrete sweat.

Synovia

Fluid secreted by the synovial membrane and found in joint cavities.

System

Group of organs that work together to perform complex body functions.  For example, the cardiovascular system consists of the heart, blood vessels, and blood.  Its function is to transport nutrients and oxygen to the cells and remove carbon dioxide and other waste products.

Tarsal bones

Ankle bones.

Tendon

Band of fibrous connective tissue that attaches muscle to bone.

Testis, or testicle (pl. Testes, or testicles)

Primary male sex organs, paired, oval-shaped, and enclosed in a sac called the scrotum.  The testes produce spermatozoa (sperm cells) and the hormone testosterone.

Testosterone

The principle male sex hormone.  Its chief function is to stimulate the development of the male reproductive organs and secondary sex characteristics such as facial hair.

Thoracic cavity

Space containing the heart, aorta, lungs, esophagus, trachea, and bronchi.

Thoracic vertebrae (T1 to T12)

Second set of 12 vertebrae; they articulate with the 12 pairs of ribs to form the outward curve of the spine.

Thymus gland

One of the primary lymphatic organs, it is located anterior to the ascending aorta and posterior to the sternum between the lungs.  It helps in the development of the body's immune system, particularly from infancy to puberty.  Around puberty the thymus gland atrophies into connective tissue and does not function.

Thyroid gland

Largest endocrine gland.  It is located in the neck below the larynx and comprises bilateral lobes connected by an isthmus.  The thyroid gland secretes the hormones triiodothyronine (T3) and thyroxine (T4), which require iodine for their production.  Thyroxine is necessary for body cell metabolism.

Thyroid-stimulating hormone (TSH)

Stimulates the thyroid gland.

Tibia and fibula

Lower leg bones.

Tissue

Group of similar cells that performs a specific task.

Tongue

Consists mostly of skeletal muscles; attached in the posterior region of the mouth.  It provides movement of food for mastication, directs food to the pharynx for swallowing, and is a major organ for taste and speech.

Tonsils

Lymphoid tissue located behind the mouth.

Trachea (windpipe)

Passageway for air to the bronchi.

Transverse plane

Horizontal field dividing the body into upper and lower portions.

Tricuspid valve

Located between the right atrium and right ventricle.

Tympanic membrane (eardrum)

Semitransparent membrane that separates the external auditory meatus and the middle ear cavity.

Ulna and radius

Lower arm bones.

Umbilical region

Around the navel (umbilicus).

Ureters

Two slender tubes, approximately 10 to 13 inches (26 to 33 cm) long, that receive the urine from the kidneys and carry it to the posterior portion of the bladder.

Urethra

Lowest part of the urinary tract, through which the urine passes from the urinary bladder to the outside of the body.  This narrow tube varies in length by sex.  It is 1.5 inches (3.8 cm) long in the female and 8 inches (20 cm) in the male, in whom it is also part of the reproductive system.  It carries seminal fluid (semen) at the time of ejaculation.

Urinary bladder

Muscular, hollow organ that temporarily holds the urine.  As it fills, the thick, muscular wall becomes thinner, and the organ increases in size.

Urinary meatus

Opening through which the urine passes to the outside.

Uterus

Pear-sized and pear-shaped muscular organ that lies in the pelvic cavity, except during pregnancy when it enlarges and extends up into the abdominal cavity.  Its functions are menstruation, pregnancy, and labor.

Uvula

Soft V-shaped mass that extends from the soft palate.  Directs food into the throat.

Vagina

A 3-inch (7-8 cm) tube that connects the uterus to the outside of the body.

Vas deferens, ductus deferens, or seminal duct

Duct carrying the sperm from the epididymis to the urethra.  (The urethra also connects with the urinary bladder and carries urine outside the body.  A circular muscle constricts during intercourse to prevent urination.)

Veins

Blood vessels that carry blood to the heart.  All veins, with the exception of the pulmonary veins, carry blood containing carbon dioxide and other waste products.  The pulmonary veins carry oxygenated blood from the lungs to the heart.

Venae cavae

Largest veins in body.  The inferior vena cava carries blood to the heart from body parts below the diaphragm, the superior vena cava carries blood to heart from upper body part of the body.

Ventricles

Spaces within the brain that contain a fluid called cerebrospinal fluid.  The cerebrospinal fluid flows through the subarachnoid space around the brain and spinal cord.

Venules

Smallest veins.

Vertebral column

Made up of bones called vertebrae (sing. Vertebra) through which the spinal cord runs.  The vertebral column protects the spinal cord, supports the head, and provides a point of attachment for ribs and muscles.

Visceral pericardium

Lies closest to the myocardium.

Vitreous humor

Jelly-like substance found behind the lens in the posterior cavity of the eye that maintains its shape.

Vulva, or external genitals

Two pairs of lips (labia major and labia minora) that surround the vagina.

Xiphoid process

Lower portion of the sternum.

Yellow marrow

Soft, fatty material found in the medullary cavity of long bones.

Zygote

Cell formed by the union of the sperm and the ovum.

Types of body movements

Abduction

Movement of drawing away from the middle.

Adduction

Movement of drawing toward the middle.

Inversion

Turning inward.

Eversion

Turning outward.

Extension

Movement in which a limb is placed in a straight position.

Flexion

Movement in which a limb is bent.

Pronation

Movement that turns the palm down.

Supination

Movement that turns the palm up.

Rotation

Turning around its own axis.

Types of muscles

Skeletal muscles (also known as striated muscles)

Attached to bones by tendons and make body movement possible.  Skeletal muscles produce action by pulling and by working in pairs.  Also known as voluntary muscles because we have control over these muscles.

Smooth muscles (also known as unstriated muscles)

Located in internal organs such as the walls of blood vessels and the digestive tract.  They are also called involuntary muscles because they respond to impulses from the autonomic nerves and are not controlled voluntarily.

Cardiac muscle (also known as myocardium)

Forms most of the wall of the heart.  Its involuntary contractions produces the heartbeat.