Anatomical Terminology and Body Orientation

Anatomical Terminology

• Standardized language for healthcare professionals to describe body structure positions and relationships accurately.
• It provides a common frame of reference for anatomical and medical communication.
• Terms include anatomical position, direction, planes, and regions.

Anatomical Position

• The reference stance has the body erect, feet slightly apart, and palms facing forward.
• It provides a standard frame of reference for anatomical descriptions.

Anatomical Direction

• Describes the location of structures relative to others.
• Common terms include superior (above), inferior (below), anterior (front), posterior (back), lateral (away from the midline), and medial (towards the midline).
• Proximal refers to being closer to the point of attachment or origin.
• Distal refers to being farther from the point of attachment or origin.

Planes of the Body

• The coronal (frontal) plane divides the body into anterior (front) and posterior (back) sections.
• The transverse (cross-sectional) plane divides the body into superior (top) and inferior (bottom) sections.
• The sagittal (median) plane divides the body into left and right sections.

Regional Terms

• Designate specific body areas for precise location.
• Dorsal relates to the back.
• Lumbar relates to the lower back.
• Umbilical relates to the navel.
• Crural relates to the shin.
• Orbital relates to the eye region.
• Patellar relates to the front of the knee.
• Oral relates to the mouth.
• Nasal relates to the nose.
• Buccal relates to the cheek.
• Ocular relates to the eye.
• Occipital relates to the back of the head.
• Digital/Phalangeal relates to the fingers or toes.

Respiratory System Overview

• The respiratory system facilitates gas exchange, mainly oxygen intake and carbon dioxide removal.
• Key components include the lungs, trachea, bronchi, bronchioles, and alveoli, ensuring ventilation and respiration.
• The heart's pulmonary system transports both oxygen and carbon dioxide throughout the body.

Lung Anatomy

• Lungs are located in the thoracic cavity, protected by the pleura (double membrane).
• The right lung has three lobes (superior, middle, and inferior) and is larger due to the heart's placement, which allows more space.
• The left lung has two lobes (superior and inferior).
• The trachea connects the larynx to the lungs (windpipe).
• Bronchi are the main passageways directly attached to the lungs.
• Bronchioles are smaller tubes branching from the bronchi, connecting to alveoli.

Alveoli

• Tiny air sacs are the sites of gas exchange.
• Type I alveolar cells form the alveolar wall.
• Type II alveolar cells release surfactant which is a lipoprotein that reduces surface tension.
• The mediastinum is the area between the two lungs where the heart is located.

Ventilation

• Ventilation is the exchange of oxygen with carbon dioxide in the lungs,
• The mechanism is a combination of muscle action and negative pressure.
• Diaphragm and intercostal muscles contract to decrease pressure, increase lung volume, and draw air in.
• Relaxation of these muscles reduces lung volume, increases pressure, and expels air.
• The process includes periodic inspiration( the inhalation of air) and periodic expiration (the expulsion of air).
• Tidal volume is the amount of air breathed in and out during a normal breath.

Gas Exchange

• Gas exchange location occurs in the Alveoli
• Gas exchange occurs through diffusion, which is passive transport from high to low concentration.
• Oxygen diffuses into the blood capillaries and carbon dioxide diffuses into the alveoli.
• Factors influencing diffusion rate are proportional to the surface area and the concentration gradient, and inversely proportional to the distance in solutions.
• Capillaries connect smaller arteries (arterioles) to smaller veins (venules) and carry out gas exchange.

Alveoli Details

• Tiny air sacs in the lungs enable oxygen and carbon dioxide exchange.
• Cell Types consists of Type I (alveolar wall) and Type II (surfactant release).
• Surfactant reduces surface tension to prevent alveolar collapse.
• Concentration Gradients occur with high oxygen and low carbon dioxide concentration.

Breathing Mechanics

• The diaphragm and intercostal muscles contract to increase lung volume and relax to decrease it.
• Inhalation is an active process where air is drawn into the lungs.
• Exhalation is a passive process where air is pushed out of the lungs.
• Residual volume is the remainder of air rich in carbon dioxide that stays stuck in the alveoli and mixes with incoming oxygen-rich air.

Cardiovascular/Circulatory System Overview

• The cardiovascular system circulates blood throughout the body, facilitating nutrient distribution and waste removal.
• It includes the heart, blood vessels (arteries, veins, and capillaries), and blood.

Heart Structure

• Made of cardiac muscle.
• Has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
• The right ventricle pumps blood toward the lungs.
• The right and left ventricles have thicker walls than the atria.

Blood Components

• Plasma contains nutrients, hormones, antibodies, and immune proteins.
• Red blood cells contain hemoglobin for oxygen transport.
• White blood cells defend against pathogens and include granulocytes (basophils, eosinophils, neutrophils) and agranulocytes (monocytes, lymphocytes).
• Platelets are responsible for blood clotting.

Blood Circulation

• A closed circulatory system has the blood pumped by the heart through a network of arteries, veins, and capillaries.
• The pulmonary loop carries deoxygenated blood from the right ventricle to the lungs for oxygenation and returns oxygenated blood to the left atrium.
• The systemic loop carries oxygenated blood from the left ventricle to the body and returns deoxygenated blood to the right atrium.

Systole and Diastole

• Systole is the contraction of heart muscles.
• Diastole is the relaxation of heart muscles.

Immune System Barriers Overview

• The immune system uses barriers to prevent pathogens from entering the body.
• These provide the first line of defense in preventing infections and maintaining health, where internal defenses are subsequently activated once pathogens breach these barriers.

External Barriers

• Prevent pathogens from entering the body.
• Includes physical and chemical barriers.

Internal Barriers

• Activated when external barriers are breached.
• Include inflammatory responses and defensive cells/chemicals that attack pathogens.

Physical Barriers

• The skin is a primary physical barrier.
• Mucus traps pathogens.

Chemical Barriers

• Low pH inhibits pathogen growth.
• Salt creates a hypertonic environment.
• Enzymes break down pathogens.
• Secretions such as acid, enzymes, and salt prevent pathogen entry.

Commensal Microorganisms

• Microscopic organisms live on the human body without causing harm.
• They create a cellular barrier.

Immune Response Overview

• Protects the body from disease-causing agents (pathogens) through innate and adaptive defenses.
• The innate immune system provides nonspecific, immediate responses.
• The adaptive immune system mounts specific responses and remembers pathogens.
• Key components include physical barriers, cells, and chemical signals.

Innate Immune System

• Nonspecific defense mechanisms present from birth. Includes:
  • Physical barriers: skin and mucus membranes
  • Chemical barriers: Low pH, salt, enzymes, and antimicrobial peptides
  • Internal defenses: Phagocytes, natural killer (NK) cells, interferons, and complement system

Adaptive Immune System

• A specific response to pathogens develops over time.
• Involves lymphocytes (T cells and B cells).
• Includes two types of responses:cellular (cell-mediated) and humoral (antibody-mediated)

Inflammatory Response

• Innate immune response triggered by tissue injury or infection.
• Involves histamine release, which increases blood flow and attracts phagocytes.
• May also cause fever to speed up the immune response.

Cellular Response

• Part of the adaptive immune system, mediated by T cells.
• Targets and destroys infected cells.

Humoral Response

• Part of the adaptive immune system, mediated by B cells.
• Produces antibodies to neutralize pathogens in body fluids.

T Cells

• Lymphocytes that mature in the thymus.
• Key players in cellular immunity.

B Cells

• Lymphocytes that mature in the bone marrow.
• Produce antibodies in humoral immunity.

Antigen-Presenting Cells (APCs)

• Cells that digest pathogens and present antigens to T cells.
• Examples: Macrophages.
• They activate helper T cells.

Helper T Cells

• Secrete cytokines to activate cytotoxic T cells and B cells.
• Coordinate the adaptive immune response.

Cytotoxic T Cells

• Destroy infected cells displaying specific antigens.
• Activated by helper T cells.

Explore the foundational concepts of anatomical terminology and orientation. This includes anatomical planes, regional terms, relative positions, and basic functions of body systems. Learn to accurately describe body parts and their relationships.