An Introduction to the Human Body Chapter 1 An Introduction to the Human Body

Definitions of A & P: Anatomy Physiology science of structure relationships revealed by dissection (cutting apart) imaging techniques Physiology science of body functions normal adult physiology studied in this text some genetic variations described Subdivisions of A & P = Table 1.1 (pg 3)

Levels of Organization Chemical atoms molecules Cellular Tissue Organs System Level Organismic Level

Levels of Structural Organization Chemical Level atomic and molecular level Cellular level smallest living unit of the body Tissue level group of cells and the materials surrounding them that work together on one task 4 basic tissue types epithelium, muscle, connective tissue, and nerve

Levels of Structural Organization Organ level grouping of 2 or more tissue types into a recognizable structure with a specific function. Organ system collection of related organs with a common function sometimes an organ is part of more than one system Organismic level one living individual.

Clinical Observational Techniques (Non-invasive Techniques) Palpation feel body surface with hands pulses and breathing rates Can detect enlarged organs Auscultation listen to body sounds with stethoscope abnormal fluid in lungs Percussion tap on body surface and listen to echo air in intestines, Fluid in lungs

Interaction of Organ Systems All major body systems will be examined Interaction of different systems of the body skin produces vitamin D needed for calcium absorption and bone growth bone marrow produces cells which help the skin resist infection.

Life Processes Metabolism = sum of all chemical processes breakdown of large molecules into small building new structural components (proteins) providing chemical energy for cells Responsiveness detect & respond to changes in internal or external environment some typical responses muscle contraction, electrical signals, hormone or glandular secretion

Life Processes Movement at any structural level Growth Differentiation the body, an organ, a cell or cell component Growth increase in number or size of cells or the material found between cells Differentiation specialization of cells for a specific function stem cells give rise to cells that specialize Reproduction formation of new cells or new individuals

Autopsy Postmortem examination of body by dissection Purpose confirm or determine cause of death support findings of other tests provide information on effects of drug usage educate healthcare students reveal congenital defects

“Autopsy is a Slice of Real -Life CSI” Video

Homeostatis Maintaining the internal environment within physiological limits First described by French physiologist, 1813-1878 Process named by Walter Cannon, 1871-1945 Example blood glucose level is kept within narrow range 70-110/100ml

Homeostasis of Body Fluids Maintaining volume and composition Delineation of fluid compartments intracellular fluid (ICF) = within cells extracellular fluid (ECF) = outside cells intercellular fluid = tissue fluid = interstitial fluid plasma = fluid portion of blood Composition of fluids change as substances move between compartments nutrients, oxygen, ions and wastes move in both directions across capillary walls

Control of Homeostasis Homeostasis is continually being disrupted by external stimuli or intense heat, cold , and lack of oxygen internal stimuli psychological stresses exercise Disruptions are usually mild & temporary If homeostasis is not maintained, death may result

Neural and Endocrine Controls Process of maintaining a controlled condition sensory receptors detect change in a monitored variable nervous system and/or endocrine system responds Example of control of blood gas level exercise increases blood CO2 levels sensory receptors detect change nervous system increases heart and breathing rates to remove excess CO2 adrenal gland releases epinephrine to increase heart and breathing rates

Components of Feedback Loop Receptor monitors a controlled condition Control center determines next action Effector receives directions from the control center produces a response that changes the controlled condition

Negative & Positive Feedback Loops Negative feedback loop original stimulus reversed most feedback systems in the body are negative used for conditions that need frequent adjustment body temperature, blood sugar levels, blood pressure Positive feedback loop original stimulus intensified seen during normal childbirth

Homeostasis of Blood Pressure Pressure receptors in walls of certain arteries detect an increase in BP blood Pressure = force of blood on walls of vessels Brain receives input and signals heart and blood vessels Heart rate slows and arterioles dilate (increase in diameter) BP returns to normal

Positive Feedback during Childbirth Stretch receptors in walls of uterus send signals to the brain Brain releases hormone (oxytocin) into bloodstream Uterine smooth muscle contracts more forcefully More stretch, more hormone, more contraction etc. Cycle ends with birth of the baby & decrease in stretch

Homeostatic Imbalances Disorder = abnormality of structure or function Disease = homeostatic imbalance with distinct symptoms---changes in body function felt by the patient such as nausea and anxiety signs----changes in body function that can be observed by the doctor such as rash or fever Epidemiology----how disease is transmitted Pharmacology --- how drugs used to treat disease Diagnosis---skill of distinguishing one disease from another

Basic Anatomical Terminology Anatomical position Regions of the body Anatomical planes, sections and directional terms

Anatomical Position Standardized position from which to describe directional terms standing upright facing the observer, head level eyes facing forward feet flat on the floor arms at the sides palms turned forward A reclining body? Prone position = lying face down Supine position = lying face up

Clinical terminology based on a Greek or Latin root word.

Planes and Sections A plane is an imaginary flat surface that passes through the body. A section is one of the 2 surfaces (pieces) that results when the body is cut by a plane passing through it.

Sagittal Plane Sagittal plane Midsagittal plane Parasagittal plane divides the body or an organ into left and right sides Midsagittal plane produces equal halves Parasagittal plane produces unequal halves

Other Planes and Sections Frontal or coronal plane divides the body or an organ into front (anterior) and back (posterior) portions Transverse(cross-sectional) or horizontal plane divides the body or an organ into upper (superior) or lower (inferior) portions Oblique plane some combination of 2 other planes

Planes and Sections of the Brain (3-D anatomical relationships revealed) Horizontal Plane Frontal Plane Midsagittal Plane

Major Directional Terms See Definitions page 14

Superior or Inferior Superior Inferior towards the head The eyes are superior to the mouth. Inferior away from the head The stomach is inferior to the heart.

Dorsal or Ventral Dorsal or Posterior Ventral or Anterior at the back of the body The brain is posterior to the forehead. Ventral or Anterior at the front of the body The sternum is anterior to the heart.

Medial or Lateral Medial Lateral nearer to the midline of the body The heart lies medial to the lungs. Lateral farther from the midline of the body The thumb is on the lateral side of the hand.

Proximal or Distal Proximal Distal nearer to the attachment of the limb to the trunk The knee is proximal to the ankle. Distal farther from the attachment of the limb to the trunk The wrist is distal to the elbow.

Body Cavities Spaces within the body Help protect, separate, and support internal organs Separates by bones, ligaments, and muscles

Dorsal Body Cavity Near dorsal surface of body 2 subdivisions cranial cavity holds the brain formed by skull vertebral or spinal canal contains the spinal cord formed by vertebral column Meninges line the cranial cavity and the vertebral canal

Ventral Body Cavity Near ventral surface of body trunk 2 subdivisions thoracic cavity above diaphragm abdominopelvic cavity below diaphragm Diaphragm = large, dome-shaped muscle Organs called viscera Organs covered with serous membrane

Abdominopelvic Cavity Inferior portion of ventral body cavity below diaphragm Encircled by abdominal wall, bones & muscles of pelvis Subdivided into Abdominal and pelvic cavities

Abdominopelvic Cavity Abdominal Cavity: stomach, spleen, liver, gallbladder, small intestine, most of the large intestine. Pelvic Cavity: urinary bladder, portions of the large intestine, and internal organs of reproduction

Thoracic Cavity A.K.A. – Chest Cavity Encircled by ribs, sternum, vertebral column and muscle Divided into 2 pleural cavities by mediastinum Mediastinum contains all thoracic organs except lungs

Mediastinum Midline wall of tissue that contains heart and great vessels, esophagus, trachea and thymus.

Serous Membranes Thin slippery membrane lines body cavities not open to the outside parietal layer lines walls of cavities visceral layer covers viscera within the cavities Serous fluid reduces friction

Pleural & Pericardial Cavities Visceral pleura clings to surface of lungs --- Parietal pleura lines chest wall Visceral pericardium covers heart --- Parietal pericardium lines pericardial sac

Peritoneum Visceral peritoneum --- serous membrane that covers the abdominal viscera Parietal peritoneum --- serous membrane that lines the abdominal wall

Abdominopelvic Regions & Quadrants Describe locations of organs or source of pain Tic-tac-toe grid or intersecting lines through navel

Medical Imaging Allows visualization of structures without surgery Useful for confirmation of diagnosis Examples: radiography, MRI, CT, Ultrasound, PET, Radionuclide scanning, & Endoscopy

Conventional Radiography A.K.A – X-ray A single burst of xrays Produces 2-D image on film Inexpensive, quick, and simple to perform Bones appear white Hollow structures are black Skin, fat, and muscle appear varying shades of gray

Other types of Radiography Mammography Bone Densitometry Angiography Intravenous urography Barium contrast x-ray Breast Bone density Blood vessels Urinary system Gastrointestinal tract

Computed Tomography (CT Scan) Moving x-ray beam Image produced on a video monitor of a cross-section through body Computer generated image reveals more soft tissue detail kidney & gallstones Multiple scans used to build 3D views Most beneficial in screening for lung cancer, coronary artery disease, and kidney cancer

Digital Subtraction Angiography(DSA) Radiopaque material injected into blood vessels Before and after images compared with a computer program Image of blood vessel is shown on a monitor Can locate blocked blood vessels

Ultrasound (US) High-frequency sound waves emitted by hand-held device Safe, noninvasive & painless Image or sonogram is displayed on video monitor Used for fetal ultrasound and examination of pelvic & abdominal organs, heart and blood flow through blood vessels Also to observe the size, location, and actions of organs and blood flow through blood vessels

Magnetic Resonance Imaging (MRI) Body exposed to high-energy magnetic field Protons align themselves relative to magnetic field Pulse of radiowaves used to generate an image on video monitor Can not use on patient with metal in their body Reveals fine detail within soft tissues Used to detect tumors, fatty plaques, brain abnormalities, measuring blood flow, and musculoskeletal, liver, and kidney disorders

Positron Emission Tomography(PET) Substance that emits positively charged particles is injected into body Collision with negatively charged electrons in tissues releases gamma rays Camera detects gamma rays & computer generates image displayed on monitor Used to study physiology of body structures, such as metabolism in the brain or heart

YouTube - RADIOLOGY