Anatomy Exam 1 (Lecture Material)

Anatomy

(to cut apart) The study of the structure of the human body.

Physiology

The study of body function. “Structure dictates function”.

Gross anatomy

Large structures, What things look like not through a microscope (ex: arm, leg).

Regional anatomy

Study of a certain region (specialize → Medschool)

Systemic anatomy

Study of how systems work.

Hierarchy of Structural Organization

1. Chemical level - Atoms form molecules and macromolecules.

2. Cellular level - Cells and their functional subunits.

3. Tissue level - A group of cells performing a common function. Four main types = epithelial, connective, muscle, and nervous tissue.

4. Organ level - A discrete structure made up of more than one tissue (ex: liver, brain, femur, heart).

5. Organ system level - Organs working together for a common purpose.

6. Organismal level - The result of all simpler levels working in unison.

Integumentary System

Forms external body covering, protects the deeper tissue form injury, synthesized vitamin D, and is the site of cutaneous receptors (pain, pressure, etc.) and sweat and oil glands.

Skeletal System

Protects and supports body organs, provides a framework for muscles, blood cells are formed within bones, and stores minerals.

Muscular System

Allows manipulation of environment, locomotion, facial expressions, posture, and production of heat.

Nervous System

Fast acting control system, responds to internal and external changes, and activated muscles and glands.

Endocrine System

Glands that secrete hormones that regulate growth, reproduction, and nutrient use.

Cardiovascular System

Blood vessels transport blood, blood carries oxygen and carbon dioxide as well as nutrients and wastes. Heart pumps blood through blood vessels.

Lymphatic System/Immunity

Picks up fluid leaked from blood vessels, returns fluid to blood, disposes of debris in the lymphatic system, houses white blood cells (lymphocytes), and mounts against foreign substances in the body.

Respiratory System

Keeps blood supplied with oxygen, removes carbon dioxide, gas exchange occurs through walls of air sacs in the lungs

Digestive System

Breaks down food into absorbable units, indigestible foodstuffs eliminated as feces.

Urinary System

Eliminates nitrogenous wastes, regulates water, electrolyte, and acid-base balance of the blood.

Male Reproductive System

Overall function is to produce offspring. Testes produce sperm and male sex hormones. Male ducts and glands aid in delivery of sperm to the female reproductive tract.

Female Reproductive System

Overall function is to produce offspring. Ovaries produce egg and female sex hormones. Female structures serve as site for fertilization and development of the fetus. Mammary glands produce milk.

Units of Measurement

Measurement in anatomy is in the metric system. Meter, centimeter, micrometer, liter, millimeter, kilogram, gram.

Anatomical Terminology

Provides standard nomenclature worldwide. Based on greek or latin.

Anatomical Position

Common visual reference point. Person stands erect with feet together and eyes forward, palms face anteriorly with the thumbs pointed away from the body.

Axial Region

Axis of the body - head, neck, and trunk.

Appendicular Region

Appendages

Superior (Cranial)

Toward the head end or upper part of a structure or the body; above.

Inferior (Caudal)

Away from the head end or toward the lower part of a structure or the body; below.

Medial

Toward or at the midline of the body; on the inner side of.

Lateral

Away from the midline of the body; on the outer side of.

Proximal

Closer to the origin of the body part or the point of attachment of a limb to the body trunk.

Distal

Further from the origin of a body part or the point of attachment of a limb to the body trunk.

Ipsilateral

On the same side.

Contralateral

On opposite sides.

Anterior (Ventral)

Toward or at the front of the body; in front of.

Posterior (Dorsal)

Toward or at the back of the body; behind.

Superficial (External)

Toward or at the body surface.

Deep (Internal)

Away from the body surface; more internal.

Sagittal Planes

Extend vertically and divide the body into right and left parts.

• Median (Midsagittal) Plane - Sagittal plane that runs along the midline.

• Parasagittal Planes - A sagittal plane offset from the midline.

Frontal (Coronal) Plane

Lies vertically and divides the body into anterior and posterior parts.

Transverse Plane

Runs horizontally and divides the body into superior and inferior parts.

Oblique Sections

Cuts made along any plane that lies diagonally between the horizontal and vertical.

The Human Body Plan

Tube-within-a-tube, Bilateral symmetry, Dorsal hollow nerve cord, Notochord and vertebrae, Segmentation (muscle segments), Brain, Lung bud, Heart, Digestive tube, and Pharyngeal pouches. Indicated by structures shared among all vertebrates.

Dorsal Body Cavity

1. Cranial cavity - upper portion of the skull that holds the brain.

2. Vertebral cavity - The long, lower portion inside the backbone (spine) that encloses the spinal cord.

Ventral Body Cavity

1. Thoracic Cavity - Divided into three parts. Two lateral parts, each containing a lung surrounded by a pleural cavity. Mediastinum - Contains the heart surrounded by the pericardial cavity, and other major thoracic organs, such as esophagus and trachea.

2. Abdominopelvic Cavity - divided into two parts, Abdominal cavity - contains the liver, stomach, kidneys, and other organs (digestive viscera). Pelvic cavity - contains the bladder, some reproductive organs, and rectum. Many organs in the abdominopelvic cavity are surrounded by a peritoneal cavity.

Serous Cavities

A fluid-filled space inside a double-layered serous membrane that surrounds a vital internal organ. Located inside body cavity. Main types: Pleura, pericardium, and peritoneum.

Parietal Serosa

Outer wall of the serous cavity and is continuous with the visceral serosa.

Visceral Serosa

Inner wall of the cavity, covers the visceral organs.

Serous fluid

Inside the serous cavities, produced by both layers of the serous membranes. This fluid allows visceral organs to slide with little friction/lubrication during movement (ex: pumping heart, churning stomach).

Abdominal Quadrants

Divide the abdomen into four quadrants, right and left upper and right and left lower. Helps identify what organ is affected.

Organs in Abdomen Right Upper Quadrant

Liver and gallbladder.

Organs in Abdomen Left Upper Quadrant

Diaphragm, spleen, and stomach.

Organs in Abdomen Right Lower Quadrant

Ascending colon of large intestine, small intestine, cecum, and appendix.

Organs in Abdomen Left Lower Quadrant

Transverse colon of large intestine, descending colon of large intestine, initial part of sigmoid colon, and urinary bladder.

Microscopy

Examining small structures through a microscope.

Light Microscopy

Illuminates tissue with a beam of light (lower magnification).

Electron Microscopy

Uses beams of electrons (higher magnification).

Preparing Tissue for Microscopy

Specimen is fixed (preserved) and sectioned, stained to distinguish anatomical structures.

Acidic Stain

Negatively charged dye molecules, binds to positively charged molecules.

Basic Stain

Positively charged dye molecules, binds to negatively charged molecules.

Hematoxylin

Basic stain that stains acidic structures purple/blue.

Eosin

Acidic stain that stains basic structures pink/red.

Scanning Electron Microscopy

Provides 3D picture of whole un-sectioned surfaces.

Artifacts Under a Microscope

Have minor distortions or preserved tissues, not exactly like living tissues and organs.

X-ray

Electromagnetic waves of very short length (high energy) body either absorbs or lets the radiation through to get image. Best for visualizing bones and abnormal dense structures (appear white). Can use contrast medium like barium to allow visualization of hollow soft tissue organs.

Computed (Axial) Tomography (CT or CAT)

Takes successive X-rays around a persons full circumference, computer translates recorded information into a detailed picture of the body section. Works best for soft tissue, bone, and blood vessels.

Angiography

Contrast medium highlights vessel structure.

• Digital subtractions angiography (DSA): Images taken before and after contrast medium injection, computer subtracts before from after to identify blockage of arteries to heart wall and brain.

Positron Emission Tomography (PET)

Forms images by detecting radioactive isotopes injected into the body. Identifies areas with high metabolic rate or blood flow to visualize tumors and cancer (appear dark because they absorb energy).

Sonography (Ultrasound)

Body is probed with pulses of high frequency sound waves that echo off the body’s tissue, technique use to determine the age of a developing fetus.

Magnetic Resonance Imaging (MRI)

Produces high contrast images of soft tissues by detecting Hydrogen, distinguishes body tissues based on relative water content. Excellent for visualizing brain, joints, ligaments, and cartilage.

• fMRI: Functional MRI tracks blood oxygen to map brain activity.

Embryology

Study of the origin and development of a single individual.

Prenatal Period

• Embryonic period: first 8 weeks, establishment of the three primary germ layers, four primary tissue types, basic body plan, and all major organs.

• Fetal period: remaining 30 weeks, for growth, maturation, and differentiation.

The Basic Body Plan

1. Skin - dermis and epidermis

2. Outer body wall - trunk muscles, ribs, vertebrae

3. Body cavity and digestive tube - inner tube

4. Kidneys and gonads - deep to body wall

5. Limbs

Week 1 of Embryonic Period

Pre. Oocyte (egg) is released from ovary during ovulation.

Day 1. Fertilization - in the lateral third of uterine tube sperm meets and enters the egg, zygote is formed.

Day 2. Cleavage/divide - 4-cell stage, daughter cells formed from zygote.

Day 3. Morula - a solid cluster of 12-16 cells is formed by about 72 hours.

Day 4. Early blastocyst - morula hollows out (blastocyst cavity) and becomes a fluid filled structure of about 60 cells.

Day 6/7. Blastocyst adheres to uterine wall, implanting consists of a sphere trophoblast cells (helps form placenta) and eccentric cell cluster called the inner cell mass (forms embryo).

Most times a mother does not know at this point if the blastocyst was not attached.

Week 2 of Embryonic Period

Inner cell mass is divided into two sheets which have different fates - Bilaminar embryonic disc = Gives rise to entire rest of organism.

• Epiblast → Amniotic sac is formed by the extension of epiblast, outer membrane forms the amnion and inner membrane forms the amniotic sac cavity which is filled with amniotic fluid. This is where the embryo drinks from, breaths from, and waste goes to. Rupture of this sac is what is called “water breaking”.

• Hypoblast → Yolk sac is formed by an extension of hypoblast, digestive tube forms from yolk sac, not a major source of nutrients for embryo, forms tissues around yolk sac which give rise to earliest blood cells and blood vessels.