Anatomy 2

Introduction

Dr. Michael P. Gillespie

Chapter 1

An Introduction to the Human Body

Definitions

Anatomy – Deals with the structure of body parts – their forms and relationships.

Physiology – Deals with the functions of body parts – what they do and how they do it.

Dissection – The careful cutting apart of body parts to see their relationships.

Levels of Body Organization

Chemical level Cellular level Tissue level Organ level System level Organism

Chemical Level

Atoms – smallest units of matter that participate in chemical reactions.

Molecules – two or more atoms joined together.

Elements In Living Things

11 main elements comprise living things. C, H, O, P, K, I N, S, Ca, Fe, and Mg. CHOPKINS CaFé, Mighty Good!

Cellular Level

Molecules combine to form cells. Cells are the basic structural and functional

units of an organism. Cells are the smallest living units in the

human body. Cells are made up of organelles.

Tissues

Tissues are groups of cells and the materials surrounding them that work together to perform a particular function.

4 basic types of tissues in the human body: Epithelial tissue Connective tissue Muscle tissue Nervous tissue

Organs

Organs are composed of two or more tissues that work together to perform specific functions.

They usually have recognizable shapes.

System Level

A system consists of related organs that have a common function.

Sometimes an organ is part of more than one system.

There are eleven systems in the human body.

Organ Systems

Integumentary System Muscular System Skeletal System Nervous System Endocrine System Lymphatic and

Immune System

Cardiovascular System Respiratory System Digestive System Urinary System Reproductive Systems

Integumentary System

Components – Skin, hair, nails, sweat glands, oil glands.

Functions – Protects the body; helps regulate body temperature; eliminates wastes; makes vitamin D; detects sensations such as touch, pain, warmth, and cold.

Muscular System

Components – Muscles, tendons. Functions – Produces body movements, such

as walking; stabilizes body position (posture); generates heat.

Skeletal System

Components – Bones, joints, associated cartilages.

Functions – Supports and protects the body; aids body movements; houses cells that produce blood cells; stores minerals and lipids.

Nervous System

Components – Brain, spinal cord, nerves, special sense organs (I.e. eyes and ear).

Functions – Generates action potentials (nerve impulses) to regulate body activities; detects changes in the body’s internal and external environments, interprets these changes, and responds causing muscular contractions or glandular secretions.

Endocrine System

Components – Hormone producing glands and hormone producing cells.

Functions – Regulates body activities by releasing hormones (chemical messengers) which are transported in the blood from an endocrine gland or tissue to a target organ.

Lymphatic and Immune System

Components – Lymphatic fluid and vessels; spleen, thymus, lymph nodes, tonsils.

Functions – Returns proteins and fluids to blood; carries lipids from gastrointestinal tract to blood; includes structures that generate lymphocytes (to protect against disease-causing organisms).

Cardiovascular System

Components – Blood, heart, and blood vessels.

Functions – Heart pumps blood through vessels; blood carries oxygen and nutrients to cells and carbon dioxide and wastes away from cells; regulates acid-base balance, temperature, and water content of body fluids; components defend against disease.

Respiratory System

Components – Lungs, air passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes.

Functions – Transfers oxygen from inhaled air to blood and carbon-dioxide from blood to exhaled air; regulates acid-base balance, air flowing out through vocal cords produces sounds.

Digestive System

Components – Mouth, esophagus, stomach, small and large intestines, and anus (organs of GI tract); salivary glands, liver, gallbladder, pancreas (accessory organs).

Functions – Physical and chemical breakdown of food; absorbs nutrients, eliminates solid wastes.

Urinary System

Components – Kidneys, ureters, urinary bladder, urethra.

Functions – Produces, stores, and eliminates urine; eliminates wastes; regulates volume and chemical composition of blood; maintains acid-base balance; maintains mineral balance; helps regulate production of red blood cells.

Reproductive Systems

Components – Gonads (testes in males, ovaries in females), associated organs (uterine tubes, uterus, and vagina in females and epididymis, ductus deferens, and penis in males).

Functions – Gonads produce gametes (sperm or oocytes); gonads release hormones.

Non-invasive techniques to assess body structure and function

Inspection – the examiner observes the body for any changes that deviate from normal.

Palpation – the examiner feels the body with the surface of the hands.

Non-invasive techniques to assess body structure and function

Auscultation – the examiner listens to the body sounds to evaluate functioning of certain organs, often using a stethoscope to amplify the sounds.

Percussion – the examiner taps on the body surface with fingertips and listens to the resulting echo.

Basic Life Processes

Metabolism Responsiveness Movement Growth Differentiation Reproduction

Metabolism

The sum of all the chemical processes that occur in the body. Catabolism – The breaking down of complex

chemical substances into simpler ones. Anabolism – The building up of complex

chemical substances from simpler ones.

Responsiveness

The body’s ability to detect and respond to changes in its internal and external environment.

Movement

Motion of the whole body. Motion of individual organs. Motion of Single cells. Motion of structures inside cells.

Growth

Growth is an increase in body size that results from an increase in the size of existing cells, the number of cells, or both.

A tissue can increase in size due to an increase in the amount of material between cells (I.e. bone tissue).

Differentiation

Differentiation is a process a cell undergoes to develop from an unspecialized to a specialized state.

Each type of cell has a specialized structure and function.

Stem cells can divide and give rise to progeny that undergo differentiation.

Reproduction

The formation of new cells for tissue growth, repair or replacement.

The formation of new cells for the production of a new individual organism (through fertilization of an ovum by a sperm cell.

Anatomical Terminology

Body Positions Regional Names Directional Terms Planes and Sections Body Cavities

Body Positions

Anatomical Position The subject stands erect facing the observer, with

the head level and the eyes facing forward. The feet are flat on the floor and directed forward, and the arms are at the sides with the palms turned forward.

Prone – body lying face down. Supine – body lying face up.

Prone & Supine

Regional Names

Regions can be identified externally. Principal regions:

Head (cephalic) Neck (cervical) Trunk Upper limb Lower limb

Directional Terms

Superior (cephalic or cranial) and inferior (caudal). Anterior (ventral) and posterior (dorsal). Medial and lateral. Intermediate Ipsilateral and contralateral. Proximal and distal. Superficial and deep.

Planes and Sections

Sagittal Plane – vertical plane – divides body into right and left.

Midsaggital or median plane – equal parts Parasaggital plane – unequal parts Frontal or coronal – divides body into anterior and

posterior parts Transverse plane – divides body into superior and inferior

parts Oblique plane – angle Section – one flat surface or a 3-D structure

Body Cavities

Spaces within the body that help protect, separate, and support internal organs.

Two major cavities are the dorsal and ventral body cavities.

Dorsal Body Cavity

Located near the dorsal (posterior) surface of the body.

Subdividions Cranial cavity Vertebral (spinal) canal

Meninges

Ventral Body Cavity

Located near the ventral (anterior) aspect of the body.

Subdivisions Thoracic cavity Abdominopelvic cavity

Diaphragm Viscera

Thoracic Cavity

Subdivisions Pericardial Cavity Pleural cavities mediastinum

Abdominopelvic cavity

Subdivisions Abdominal Cavity Pelvic Cavity

Thoracic and Abdominal Cavity Membranes

Serous membrane Pleura Pericardium Peritoneum

Abdominopelvic Regions and Quadrants

The nine-region designation is used for anatomical studies, whereas the quadrant designation is used to locate the site of pain, tumor, or some other abnormality.

Abdominopelvic Regions

Right Hypochondriac Region Epigastric Region Left Hypochondriac Region Right Lumbar Region Umbilical Region Left Lumbar Region Right Inguinal (Iliac) Region Hypogastric (Pubic Region) Left Inguinal (Iliac) Region Subcostal line, transtubercular line, midclavicular lines

Abdominopelvic Quadrants

Right Upper Quadrant (RUQ) Left Upper Quadrant (LUQ) Right Lower Quadrant (RLQ) Left Lower Quadrant (LLQ) Horizontal lines passes through umbilicus

Homeostasis

The French physiologist Claude Bernard proposed that cells live in a relatively constant internal environment -“le milieu interieur”- despite changes in the organisms’ external environment.

The American physiologist Walter Bradford Cannon coined the term homeostasis to describe this constancy.

Homeostasis Continued…

Homeo = sameness; Stasis = standing still. The condition of equilibrium in the body’s

internal environment. Various regulatory processes in the body

maintain this condition. Dynamic condition.

Body Fluids

An important aspect of homeostasis is maintaining the volume and composition of body fluids.

Intracellular fluid ICF – intra = inside. Extracellular fluid ECF = extra = outside. Various substances are dissolved in the water

of ICF and ECF.

Dissolved Substances

Oxygen Nutrients Proteins Ions

Interstitial Fluid

The extracellular fluid that fills the narrow spaces between cells of tissues is known as interstitial fluid.

Inter = between. For cells to function properly, the

composition of the surrounding fluid must be precisely regulated.

Types of Interstitial Fluid

Blood plasma = ECF within blood vessels Lymph = ECF within lymphatic vessels Cerebrospinal fluid = ECF around the brain

and spinal cord Synovial fluid = ECF in the joints Aqueous humor and vitreous body = ECF in

the eyes

Internal Environment

Interstitial fluid surrounds all of the body’s cells and is therefore referred to as the “internal environment” of the body.

Exchange of Materials

Substances move back and forth between the interstitial fluid and the blood plasma.

This exchange occurs at the blood capillaries. The exchange occurs as a result of diffusion

(passive transport) and active transport. Movement of substances occurs in both

directions across capillary walls.

Diffusion

Diffusion or passive transport is the movement of substances from a region of higher concentration to a region of lower concentration.

Diffusion

Substances move down their concentration gradient.

Factors Influencing Diffusion

Steepness of the concentration gradient. Temperature. Mass of the diffusing substance. Surface area. Diffusion distance.

Active Transport

In active transport, substances move from a region of lower concentration to a region of higher concentration. This requires energy in the form of ATP.

Disturbance of Homeostasis

Homeostasis is constantly being disturbed. External disruptions. Internal disruptions. Regulatory systems bring the body back into

balance. Nervous system – nerve impulses – typically cause

rapid changes. Endocrine system – hormones – work slowly.

Feedback Systems

A cycle of events in which the body is continually monitored, evaluated, changed, remonitored, reevaluated, and so on.

Each monitored variable is a controlled condition.

Stimulus – a disruption that changes a controlled condition.

3 Components of a Feedback System

Receptor Control center Effector

Receptor

A body structure that monitors changes in a controlled condition and sends input to a control center.

Input is in the form of nerve impulses or chemical signals.

Control Center

The control center sets the acceptable range of values for a controlled condition.

The control center evaluates input from receptors. The control center generates output commands as

needed. Output – nerve impulses, hormones, chemical

signals.

Effector

A body structure that receives output from the control center.

Produces a response or effect that changes the controlled condition.

Feedback Loop

The system “feeds back” to change the controlled condition in some way.

Feedback systems can produce either negative feedback or positive feedback.

Negative Feedback Systems

If the response reverses the original stimulus, the system is operating by negative feedback.

Positive Feedback Systems

If the response enhances or intensifies the original stimulus, the system is operating by positive feedback.

Homeostatic Imbalances

As long as the body’s controlled conditions stay within certain narrow limits, body cells function efficiently and the body stays healthy. Homeostasis is maintained.

If homeostatic imbalance is moderate, a disorder or disease may occur; If it is severe, death may result.

Homeostatic Imbalances Continued…

Disorder – any derangement or abnormality of function.

Disease – a more specific term for an illness characterized by a specific set of signs and symptoms. Local disease. Systemic disease.

Homeostatic Imbalances Continued…

Symptoms – subjective changes in body functions that are not apparent to an observer. Headache, nausea, anxiety.

Signs – objective changes that a clinician can observe and measure. Anatomical – swelling, rash. Physiological – fever, high BP, paralysis.

Epidemiology

The science that deals with why, when, and where diseases occur and how they are transmitted to individuals.

Epi- upon. Demi - people.

Pharmacology

The science that deals with the effects and uses of drugs.

Pharmac = drug.

Diagnosis

The science and skill of distinguishing one disorder or disease from another.

Dia – through. -Gnosis – knowledge. Working diagnosis.

Information Utilized to Obtain a Diagnosis

The patient’s signs and symptoms Medical history (S.O.A.P. Notes, review of

systems, personal history, family history, medicines taken, etc.)

Physical examination (inspection, palpation, auscultation, percussion, vital signs)

Laboratory tests