Anatomy and Physiology: Directional Terms

Chapter 1: Introduction to Human Anatomy and Physiology

• Directional terms describe the relative location of body parts.
• Superficial refers to being near the surface; the skin is an example when compared to the muscles.
• Deep refers to parts more internal; the dermis is the deep layer of the skin.
• Distal indicates a body part farther from the trunk's attachment point; the hand is distal to the shoulder.
• Proximal indicates a body part closer to the trunk's attachment point; the elbow is proximal to the wrist.
• Inferior means a body part is below another; the neck is inferior to the head.
• Superior means a body part is above another; the thoracic cavity is superior to the abdominopelvic cavity.
• Lateral means toward the side, away from the midline; the ears are lateral to the eyes.
• Medial means closer to the midline; the nose is medial to the eyes.
• Relative position helps describe the position of structures within the body in relation to each other.
• Body planes are used for anatomical reference.
• The Sagittal plane divides the body into right and left halves, running vertically from front to back.
• The Frontal (coronal) plane divides the body into anterior and posterior portions, running vertically from side to side.
• The Transverse (horizontal) plane divides the body into superior and inferior portions, running horizontally across the body.
• The abdomen is divided into nine regions for descriptive purposes.
• The Epigastric region is the upper middle portion.
• The Right Hypochondriac region is in the upper right, including the liver and gallbladder.
• The Left Hypochondriac region is in the upper left, including parts of the stomach, spleen, and left kidney.
• The Right Lateral region is in the middle right, containing parts of the large intestine and right kidney.
• The Umbilical region is the middle portion, containing parts of the small intestine, transverse colon, and kidneys.
• The Left Lateral region is in the middle left, containing parts of the large intestine and left kidney.
• The Right Inguinal region is in the lower right, including the appendix and the right ovary in women.
• The Pubic region is in the lower middle, containing the bladder and parts of the small intestine.
• The Left Inguinal region is in the lower left, including parts of the large intestine and the left ovary in women.
• The body is also separated into four quadrants: right upper, left upper, right lower, and left lower.
• The appendix is located in the right lower quadrant (RLQ), specifically in the right iliac (inguinal) region.
• Levels of organization in the body range from chemical to organismal.
• The chemical level is the simplest, composed of atoms forming molecules like water, proteins, lipids, and DNA.
• The cellular level includes cells, the basic unit of life, composed of macromolecules like proteins, carbohydrates, lipids, and nucleic acids, such as muscle cells, red blood cells, and nerve cells.
• The tissue level comprises groups of cells working together for a specific function; four types include epithelial, connective, muscle, and nervous tissues.
• The organ level is where groups of tissues form organs, such as the heart, lungs, kidneys, and stomach.
• The organ system level involves groups of organs working closely together; there are 11 main organ systems, including the cardiovascular and digestive systems.
• The organism level represents the entire living human being, where all organ systems function together to support life.
• Characteristics of life include:
• Growth: Increase in cell number and size, leading to increased body size.
• Reproduction: Production of new cells and organisms.
• Responsiveness: Reaction to changes inside or outside the body.
• Movement: Change in body position or location, including motion of internal fluids and organs.
• Metabolism: The sum of all chemical reactions in a living system, including energy transformation and nutrient cycling.
• Respiration: Capturing energy by taking in oxygen and giving off carbon dioxide.
• Digestion: Breaking down food into useful nutrients for absorption.
• Circulation: Moving chemicals and cells through body fluids.
• Excretion: Removing waste products.
• The anatomical position is defined as standing erect, face forward, with upper limbs at the sides and palms forward.

Chapter 5: Tissues

• The human body consists of four main tissue types, each with distinct structures and functions.
• Epithelial tissues are found throughout the body, providing protection, secretion, absorption, and excretion; they cover the body's surface, line internal organs, and form glands.
• Connective tissues have many roles, including binding, supporting, protecting, filling spaces, storing fat, and producing blood cells; found widely throughout the body.
• Muscle tissue generates forces for movement; it is attached to bones, in the walls of internal hollow organs, and in the heart.
• Nervous tissue conducts impulses for coordination, regulation, integration, and sensory reception; located in the brain, spinal cord, and nerves.

Chapter 6: Integumentary System

• The skin has two major layers: the epidermis and the dermis.
• The epidermis is the thin, outer layer made of squamous epithelium.
• The dermis is the thicker, inner layer consisting of connective tissue, blood vessels, smooth muscle, and nervous tissue.
• A basement membrane separates and anchors the epidermis from/to the dermis.
• The dermis contains nerve fibers, sensory receptors, hair follicles, sebaceous glands, and sweat glands.
• Fibers provide toughness and elasticity to the skin.
• The border between the epidermis and dermis is uneven due to epidermal ridges.
• Dermal blood vessels carry nutrients to the upper skin layers and regulate body temperature.
• The dermis consists of areolar and dense connective tissue with collagen and elastic fibers within a gel-like ground substance.
• The epidermis consists of stratified squamous epithelium and lacks blood vessels.
• Consists of 4 layers in most parts, 5 layers in thick skin
• The stratum basale is the deepest layer consisting of dividing cells nourished by dermal blood vessels.
• Basal cells divide, older cells (keratinocytes) migrate toward the skin surface.
• As keratinocytes migrate outward, they harden, dehydrate, die, and undergo keratinization.
• The epidermis protects against water loss, mechanical injury, and microorganisms.
• The four layers of the epidermis are found in all areas of the body: stratum basale, stratum spinosum, stratum granulosum, and stratum corneum.
• The stratum corneum is the outermost layer consisting of dead, flattened, keratinized cells continually shed from the outer skin surface.
• The stratum lucidum is only found in thick skin, such as the palms and soles, located between the stratum granulosum and stratum corneum.
• Melanocytes are specialized cells that produce melanin, the skin pigment.
• Melanocytes are found in the deepest layer of the epidermis and in the dermis.
• Melanin protects the DNA of skin cells from the damaging effects of UV radiation.
• Melanin pigment provides skin and hair color; more melanin results in darker skin or hair.
• EUmelanin is brownish-black, and pheomelanin, found in areas like the lips, is reddish-yellow.
• All people have about the same number of melanocytes.
• Skin color is genetically determined by the amount of melanin produced, as well as the size and distribution of melanin granules.
• Combination of genetic, environmental, and physiological factors affects skin color.
• Sunlight, UV light (from sun lamps and x-rays) exposure darkens skin due to increased melanin production.
• Oxygen-rich blood gives light-skinned people a pinkish tone due to hemoglobin.
• Oxygen-poor blood gives light-skinned people a blush appearance, known as cyanosis.
• Diet and disease can affect skin color; too many orange or yellow foods with carotene can cause yellowish skin, and jaundice (due to liver disease) can cause bright yellow skin.

Chapter 7: Skeletal System

• The human skeleton consists of 206 bones, divided into the axial skeleton (80 bones) and the appendicular skeleton (126 bones).
• The vertebral column extends from the skull to the pelvis, forming the skeleton's vertical axis, supporting the head and trunk and protecting the spinal cord.
• The vertebral column (spine) is divided into five regions:
• Cervical: Neck, consisting of 7 vertebrae (C1-C7).
• Thoracic: Upper back, consisting of 12 vertebrae (T1-T12).
• Lumbar: Lower back, consisting of 5 vertebrae (L1-L5).
• Sacral: Forms the base of the vertebral column, consisting of 5 vertebrae (S1-S5).
• Coccyx: Tailbone, consisting of 4 vertebrae (C1-C4).
• Types of fractures include:
• Transverse fracture: A complete break at a right angle to the bone's axis.
• Greenstick fracture: An incomplete break on the convex surface of the bend in the bone, common in children.
• Oblique fracture: A fracture that occurs at an angle other than a right angle to the bone's axis.
• Comminuted fracture: A complete fracture where the bone fragments are shattered.
• Spiral fracture: A fracture caused by excessive twisting of the bone.
• Bones are classified into:
• Long bones: Having long longitudinal axes and expanded ends (e.g., forearm and thigh bones) are longer than they are wide.
• Short bones: Having roughly even lengths and widths (e.g., wrist and ankle bones, also known as carpals and tarsals).
• Flat bones: Platelike structures with broad surfaces, thin, flat, and often curved (e.g., skull, ribs, and sternum).
• Synarthrosis joints are a type of fibrous joint that is immovable, characterized by very little to no movement.
• Synarthroses provide stability and protection.
• Examples include sutures in the skull and gomphosis (joint between a tooth and its socket).
• The appendicular skeleton consists of the bones of the upper and lower limbs and the bones that anchor those limbs to the axial skeleton.
• Consists of 126 bones.
• Examples include arms, legs, pelvic girdle, and pectoral girdle.
• The axial skeleton supports and protects the organs of the head, neck, and trunk.
• Consists of 80 bones.
• Examples include the skull, vertebral column, ribs, sternum, thoracic cage, and hyoid bone.
• Functions of bone:
• Bones give shape to structures (head, face, thorax, limbs) and provide support.
• Bones provide a structural framework that supports the body and cradles soft tissues and organs.
• Bones protect vital organs, like the skull protecting the brain and the rib cage protecting the heart and lungs.
• Movement depends on bones, which are attached to muscles; muscle contraction pulls on bones, allowing movement.
• Blood cell production occurs in bone marrow, which produces red blood cells, white blood cells, and platelets.
• Energy storage happens as bones store lipids (fat) in the yellow bone marrow, serving as an energy reserve.
• Cartilage serves as a flexible, rubbery template for bone formation, crucial during fetal development and childhood.
• Hyaline cartilage is found in cartilage templates during bone formation, as well as in the joints, ribs, and respiratory tract.
• Elastic cartilage is found in structures like the ear and epiglottis.
• Fibrocartilage is found in areas requiring strength, such as the intervertebral discs and pubic symphysis.
• Bones of the pelvic girdle:
• The pelvic girdle consists of two coxal bones (hip bones, pelvic bones, innominate bones) that articulate with each other anteriorly and with the sacrum posteriorly.
• The pelvic girdle supports the trunk, provides attachments for the lower limbs, and protects the urinary bladder, distal large intestine, and internal reproductive organs.
• Two hip bones (coxal bones) each composed of three fused bones – the ilium, ischium, and pubis.
• The sacrum is part of the vertebral column.
• The coccyx (tailbone) is the final part of the vertebral column, contributing to the pelvic region.
• Ilium: the largest and uppermost portion of the hip bone, flares outward forming the prominence of the hop.
• Ischium forms the lowest portion of the hip bone, is L-shaped, pointing posteriorly and downward.
• Pubis constitutes the anterior portion of the hip bone; the two pubic bones come together at the midline, forming the pubic symphysis.

Chapter 8: Muscular System

• Muscle names:
• Pectoralis major: Large (major), located in the pectoral region (chest), involves movements of the shoulder joint.
• Deltoid: Shaped like a delta or triangle, located in the shoulder, assists in abduction of the arm, also assisting flexion, extension and rotation of the arm.
• Flexor Digitorum Longus: Located in the lower leg, on the posterior side of the tibia, flexes the toes and helps with plantar flexion of the foot.
• Biceps femoris: Part of the hamstring group, located at the back of the thigh, plays a key role in flexing the knee, extending the hip and rotating the leg when the knee is bent. Hamstring Muscles:
• Biceps femoris*: flexes the knee, extends the hip and helps with lateral rotation of the leg when the leg is flexed
• Semitendinosus*: flexes the knee, extends the hip and assists with medial rotation of the leg when the knee is bent
• Semimembranosus*: flexes the knee, extends the hip and assists with medial rotation of the leg when the knee is bent
• The general function of the hamstring muscles is knee flexion, hip extension and stabilization.
• Quadriceps Muscles:
• Rectus femoris*: extends leg at knee, flexes the thigh at the hip
• Vastus lateralis*: extends leg at the knee.
• Vastus medialis*: extends the knee.
• Vastus intermedius*: extends the knee.
• These muscles are crucial for lower body strength and function. Movements:
• Pronation*: The rotation of the forearm or foot that turns the palm downward (or facing posteriorly) or the sole of the foot inward.
• Abduction*: Abduction is the movement of a limb or body part away from the midline of the body.
• Adduction*: The movement of a limb or body part toward the midline of the body.
• Supination*: Turning the palm or foot upward/outward. Actin, troponin, and tropomyosin functions:
• Actin*: Actin is a thin filament protein that forms the basic structure of the muscle fiber.
• Troponin*: Troponin is a regulatory protein that is bound to the actin filament.
• Tropomyosin*: Tropomyosin is a regulatory protein that winds around the actin filaments and blocks the binding sites for myosin when the muscle is at rest.

Chapter 9:Nervous system

• Midbrain function*:
• The midbrain is a short section of the brainstem between the diencephalon and the pons.
• The midbrain contains the centers for visual reflexes, responsible for enabling the eyes to look at stationary objects as the head turns.
• The midbrain contains the auditory reflex centers that enable a person to move the head to hear sounds more distinctively.
• The midbrain plays a crucial role, regarding sensory processing, motor control, and the regulation of several vital systems.
• The Brain*:
• The brain is the largest, most complex portion of the nervous system, containing 100 billion multipolar neurons and many neuroglia to support the neurons.
• Cerebrum*: Largest portion, associated with higher mental functions, sensory & motor functions
• Diencephalon*: Processes sensory input and controls many homeostatic processes
• Cerebellum*: Coordinates muscular activity
• Brainstem*: Coordinates and regulates visceral activities and connects different parts of the nervous system Sensory receptors:
• Chemoreceptor*: Chemoreceptors detect chemical changes in the environment, such as changes in taste, smell, and blood chemistry.
• Mechanoreceptors*: Mechanoreceptors detect mechanical pressure or distortion in the environment, such as touch, sound, or changes in position.
• Photoreceptors*: Photoreceptors detect light and are primarily involved in vision. They convert light into electrical signals that the brain interprets as visual images.

Chapter 11: Endocrine System

• Glucagon*: Raises the blood sugar concentration by stimulating the liver to break down glycogen and convert certain noncarbohydrates, such as amino acids into glucose.
• Insulin*: Lowers the blood glucose levels, promoting facilitated diffusion of glucose into cells that have insulin receptors for use in cellular respiration.
• Parathyroid hormone*: Increase the blood calcium ion concentration and to decrease the blood phosphate ion concentration. PTH affects the bones, kidneys and intestines
• Calcitonin*: Is produced in the thyroids extrafollicular cells. It lowers blood calcium levels, Inhibiting the activity of osteoclasts (cells that break down bone tissue).
• Pituitary glands*:
• The pituitary gland is located at the base of the brain, where the pituitary stalk attaches to the hypothalamus.
• Growth hormone stimulates cells to enlarge and divide more frequently, enhances the movement of amino acids across the cell membrane and speeds the rate at which cells utilize carbohydrates and fats.
• Prolactin* stimulates and sustains a women's health production following the birth of an infant and is produced by the anterior pituitary.
• Oxytocin* stimulates uterine contractions and Stimulates milk ejection.
• Antidiuretic*: (ADH) produced by the posterior pituitary, Regulates water balance: ADH helps the kidneys retain water by increasing water reabsorption in the nephrons of the kidneys & Regulates blood pressure: ADH can cause blood vessels to constrict. Endocrine glands secrete hormones directly into the bloodstream or lymphatic system, which transport the hormones to target organs or tissues. Exocrine glands secrete enzymes or other substances into ducts, which then transport these substances to specific locations, such as body surfaces or body cavities.

Chapter 12: Blood

• Hematocrit*: The percentage of red blood cells in whole blood, about 45% of blood volume.
• Agranulocytes*: Agranulocytes are a type of white blood cell (WBC) that lack granules in their cytoplasm.
• Blood types based on antigens*: An antigen is any molecule that triggers an immune response.
• Type A: A antigens on RBCs and ANTI B antibodies
• Type B: B antigens on RBCs and ANTI A antibodies
• Type AB: Both A & B antigens on RBCs and Neither ANTI- A or ANTI- B
• Type O: Neither A or B antigens on RBCS and Both ANTI - A or ANTI - B
• RH-Positive: RH antigen on RBCs and ANTI-RH antibodies
• RH-NEGATIVE: NO RH antigens and can develop ANTI-RH antibodies
• Lifespan of RBCs*: The normal lifespan of red blood cells os 120 days. After their lifespan, RBCs are destroyed in the spleen and liver, where they are broken down.
• Erythroblastosis fetalis cause*: occurs when an Rh-negative mother carries an Rh-positive fetus. Hemostasis:Hemostasis is the process by which the body stops bleeding after injury and maintains blood flow in the vessels Chapter 13: Cardiovascular System
• Function of capillaries*: Capillaries are the smallest diameter blood vessels, connect the smallest venules.
• Levels of the heart wall*: Epicardium: The outermost layer of the heart. Myocardium: The middle layer, made up of cardiac muscle Endocardium: The innermost layer, made up of a thin layer of epithelial cells
• Function of chordae tendineae*: The chordae tendineae are strong, fibrous cords that connect the papillary muscles to the atrioventricular (AV) valves.

Pathway of blood through the heart:

1. Deoxygenated blood enters the right atrium from the superior and inferior vena cava.
2. Blood flows through the tricuspid valve into the right ventricle.
3. The right ventricle pumps the blood through the pulmonary valve into the pulmonary artery, which carries it to the lungs for oxygenation.
4. Oxygenated blood returns from the lungs to the left atrium via the pulmonary veins.
5. Blood flows through the mitral valve into the left ventricle.
6. The left ventricle pumps the oxygenated blood through the aortic valve into the aorta, from where it is distributed to the entire body. The sounds of a heartbeat are due to vibrations in the heart tissues associated with the valves closing. The heart has four main valves, and their primary function is to ensure one-way blood flow and prevent backflow

• Heart Rate* The number of times the heart beats per minute (usually measured as beats per minute (bpm)).
• Blood Pressure*: The force of blood against the walls of arteries.

Chapter 14: Lymphatic System

• Function of lymph*: Lymph is a clear, colorless fluid that circulates through the lymphatic vessels.
• Functions of Lymph nodes*: Filter lymph and remove bacteria and cellular debris before lymph is returned to the blood Immune surveillance: monitor body fluids, performed by lymphocytes and macrophages Lymph nodes are also centers of lymphocyte production
• Function of T-lymphocytes* T-lymphocytes play a crucial role in cell-mediated immunity, directly killing infected cells, coordinating the immune response, and creating memory cells for faster future immune responses.

Chapter 15: Digestive System

• Anatomical regions of the stomach*: The stomach is divided into the: Cardia: Small area near the opening of the esophageal Fundus: Balloons superior to the cardia, is a temporary storage area Body: Main part of the stomach Pylorus: Distal portion of the stomach where it approaches the small intestine Functions of digestive system: The digestive system plays a vital role in breaking down food and absorbing nutrients to fuel the body.
• Function of iron in the body*:
• Organs of the digestive system and their functions*: Mouth: the entry point for food. Esophagus: a muscular tube. Stomach: a muscular organ that stores food. Small intestine: the main site for digestion Liver: produces bile Gallbladder: stores bile produced by the liver. Pancreas: produces digestive enzymes. Large Intestine (Colon): absorbs water and salts Rectum and Anus: stores the formed stool Function of salivary amylase splits starch molecules into disaccharides.
• Swallowing has three stages.
• Parotid gland anatomy and physiology*: The parotid gland are the largest of major salivary glands
• Pathway of alimentary canal*: The alimentary canal is a tube that includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus.
• Function of uvula*: prevents food from entering the nasal cavity

Chapter 16: Respiratory system

• Processes in respiration:
  • External respiration: Ventilation or breathing allows gas exchange between capillaries in the lungs and the air.
  • Internal respiration: The transport of these gases in the blood to exchange them between all body cells.
  • Cellular respiration: Occurs in the cells' mitochondria, where oxygen is used for energy production.
• Right Lung vs. Left Lung:
  • Right Lung:
    • Larger than the left lung.
    • Has three lobes: superior, middle, and inferior.
  • Left Lung:
    • Smaller than the right lung.
    • Has two lobes: superior and inferior.
• Each lung contains air passages, alveoli, nerves, blood vesicles, lymphatic vesicles, and connective tissues.
• Anatomy of the respiratory tract: The respiratory tract is the system responsible for breathing, which involves oxygen intake and carbon dioxide expulsion.
  • Upper respiratory tract:
    • Nose.
    • Nasal cavity.
    • Paranasal sinuses.
    • Pharynx.
    • Larynx.
  • Lower respiratory tract:
    • Trachea.
    • Bronchial tree.
    • Lungs.
• Tidal Volume: Volume of air that enters or leaves the lungs during one respiratory cycle. Average resting volume is approximately 500ml.
• Vital Capacity: The maximum volume of air the lungs can hold: VC+RV (approximately 5,800mL).
• Pathway of Airflow:
  1. Nose/Mouth.
  2. Pharynx.
  3. Larynx.
  4. Trachea.
  5. Bronchi.
  6. Bronchioles.
  7. Terminal Bronchioles.
  8. Respiratory Bronchioles.
  9. Alveolar Ducts.
  10. Alveoli (Gas exchange).

Chapter 17: Urinary system

• Anatomy and physiology of the parts of the nephron:
  • Glomerulus: Renal corpuscle that consists of a tangled cluster of blood capillaries.
  • Glomerular capsule: Thin-walled, saclike structure that surrounds the glomerular and receives filtrate from the glomerulus.
  • Nephron loop: The nephron loop is the U-shaped part of the nephron in the kidney with two main sections:
    • Descending Limb: Allows water to leave, making the filtrate more concentrated.
    • Ascending Limb: Pumps out salts but doesn't let water pass, which helps dilute the filtrate.
• Anatomy and location of the kidneys:
  • The kidneys lie on either side of the vertebral column, high on the posterior wall of the abdominal cavity. They are also two bean-shaped organs located in the lower back, on either side of the spine.
  • They are responsible for filtering waste from the blood, balancing fluids, electrolytes, and producing urine, and are located in the retroperitoneal space.

Chapter 18: Water, electrolyte, acid-base balance

• Daily Water Intake: The average water intake for an adult is 3,500 milliliters.
• Routes of Water Loss:
  • 60% in urine.
  • 6% in feces.
  • 6% in sweat.
  • 28% through evaporation from skin and lungs.
• Conditions that make the pH of body fluids more acidic or more basic
  • Normal pH range of blood is 7.35 to 7.45.
  • A pH below 7.35 is acidosis.
  • A pH above 7.45 is alkalosis.
  • Acidosis results from the accumulation of acids or loss of bases.
  • Alkalosis results from the loss of acids or accumulation of bases.
  • pH of <6.8 or >8.0 is usually fatal.
• Components of Urine: Water, urea, creatinine, uric acid, electrolytes, waste products.

Chapter 19: Reproductive system

• Location of Uterine Tubes:
  • Open near the ovaries.
  • Pass medially to the uterus and opens to the uterine cavity.
  • Near each ovary, a uterine tube expands, forming an infundibulum, which encircles the ovary.
• Function of Lactiferous Ducts:
  • Responsible for carrying milk from the milk-producing glands to the nipple.
• Anatomy of Labia Majora:
  • Encloses and protects the other external reproductive organs.
• Function of Inhibin:
  • Female Reproduction: Inhibin is produced by the ovaries and helps regulate the menstrual cycle by inhibiting FSH after ovulation.
  • Male Reproduction: Inhibin is produced by the testes and helps regulate sperm production by inhibiting FSH.
• Primary Sex Organs:
  • Males: The primary sex organs are the testes, which produce sperm and the hormone testosterone.
  • Females: The primary sex organs are the ovaries, which produce eggs and the hormones estrogen and progesterone.
• Function of androgens*: Androgens are a group of hormones responsible for the development of male characteristics:
• Function of testosterone*: Testosterone is the primary male sex hormone, although it is also present in females in smaller amounts, which being the most prominent androgen.
• *Homologous male/female anatomy (clitoris and penis)**: Penis: a cylindrical organ that conveys urine and semen through the urethra to the outside. The body or shaft of the penis has three columns of erectile tissues. Clitoris: is visible as a small projection at the anterior end of the vulva between the labia minora, corresponds to the penis in males.
• Function of estrogen*: Estrogen is a hormone with several important roles. Helps control the monthly cycle, prepares for pregnancy and the development of eggs in the ovaries.
• Immune system:
• Memory cell functionMemory cells are special cells in your immune system that "remember" infections.