Human Anatomy and Physiology I INTRODUCTION Chapter 1

Chapter 1 Outline Levels of Structural Organization Maintaining Life Overview of Anatomy and Physiology Levels of Structural Organization Maintaining Life Homeostasis The Language of Anatomy

Overview of Anatomy and Physiology Anatomy: Structure Major Subdivisions: Gross or macroscopic anatomy regional, surface, and systemic Microscopic anatomy cytology and histology Developmental anatomy embryology

Overview of Anatomy and Physiology Physiology: Function Subdivisions are based on organ systems Examples: renal or cardiovascular physiology

Principle of Complementarity Anatomy and Physiology are inseparable Always be thinking Structure and Function when you study!

Levels of Structural Organization Chemical: atoms and molecules (Chapter 2) Cellular: cells and their organelles (Chapter 3) Tissue: groups of similar cells (Chapter 4) Organ: contains two or more types of tissues Organ system: organs that work closely together Organismal: all organ systems together

Levels of Structural Organization Organelle Molecule Atoms Chemical level Atoms combine to form molecules. Cellular level Cells are made up of molecules. Tissue level Tissues consist of similar types of cells. Organ level Organs are made up of different types of tissues. Organ system level Organ systems consist of different organs that work together closely. Organismal level The human organism is made up of many organ systems. Smooth muscle cell Smooth muscle tissue Blood vessel (organ) Heart Blood vessels Epithelial tissue 2 1 Cardiovascular system Cardiovascular system 3 Connective tissue 4 6 5

Overview of Organ Systems Integumentary System Forms the external body covering Protects deeper tissues from injury Synthesizes vitamin D Houses cutaneous receptors and sweat and oil glands (pain, pressure) Nails Skin Hair

Overview of Organ Systems Skeletal System Protects and supports body organs Provides framework for muscles to cause movement Blood cells are formed within bones Bones store minerals Bones Joint

Overview of Organ Systems Muscular System Allows manipulation of the environment locomotion, and facial expression Maintains posture Produces heat Skeletal muscles

Overview of Organ Systems Nervous System Fast-acting control system of the body Responds to internal and external changes by activating appropriate muscles and glands Brain Nerves Spinal cord

Overview of Organ Systems Endocrine System Glands secrete hormones Regulate body processes growth, reproduction and nutrient use (metabolism) Pineal gland Pituitary gland Thyroid Thymus Adrenal Pancreas Testis Ovary

Overview of Organ Systems Cardiovascular System The heart pumps blood Blood vessels transport blood Blood carries oxygen, carbon dioxide, nutrients, and wastes Heart Blood vessels

Overview of Organ Systems Lymphatic System/Immunity Picks up fluid leaked from blood vessels and returns it to blood Disposes of debris in the lymphatic stream Houses white blood cells (lymphocytes) involved in immunity Mounts immune response against foreign substances within the body Lymphatic vessels Red bone marrow Thoracic duct Thymus Spleen Lymph nodes

Overview of Organ Systems Respiratory System Keeps blood constantly supplied with oxygen Removes carbon dioxide Gaseous exchanges occur through the walls of the air sacs of the lungs Nasal cavity Bronchus Pharynx Larynx Trachea Lung

Overview of Organ Systems Digestive System Breaks down food into absorbable units Absorbable foodstuffs enter the blood for distribution to body cells Indigestible foodstuffs are eliminated as feces Liver Oral cavity Esophagus Large intestine Stomach Small Rectum Anus

Overview of Organ Systems Urinary System Eliminates nitrogenous wastes from the body Regulates water, electrolyte and acid-base balance of the blood Kidney Ureter Urinary bladder Urethra

Overview of Organ Systems Reproductive System Production of gametes, hormones and ultimately offspring Prostate gland Ductus deferens Penis Testis Scrotum Ovary Uterine tube Mammary glands (in breasts) Uterus Vagina Male Reproductive System Female Reproductive System

Organ System Interrelationships Digestive system Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces) Respiratory system Takes in oxygen and eliminates carbon dioxide Food O2 CO2 Cardiovascular system Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs Interstitial fluid Nutrients Urinary system Eliminates nitrogenous wastes and excess ions Nutrients and wastes pass between blood and cells via the interstitial fluid Integumentary system Protects the body as a whole from the external environment Blood Heart Feces Urine Cells and organs work cooperatively in the body to maintain well being

Homeostasis Maintenance of a relatively stable internal environment despite continuous outside changes A dynamic state of equilibrium

Homeostatic Control Mechanisms Involve continuous monitoring and regulation of many factors Nervous and Endocrine systems accomplish the communication via nerve impulses and hormones

Components of a Control Mechanism Receptor (sensor) Monitors the environment Responds to stimuli (changes in controlled variables) Control center Determines the set point at which the variable is maintained Receives input from receptor Determines appropriate response

Components of a Control Mechanism Effector Receives output from control center Provides the means to respond Response acts to reduce or enhance the stimulus (feedback)

Components of a Control Mechanism Stimulus produces change in variable. BALANCE IMBALANCE 1

Components of a Control Mechanism Stimulus produces change in variable. Receptor detects change. Receptor BALANCE IMBALANCE 1 2

Components of a Control Mechanism Stimulus produces change in variable. Receptor detects change. Input: Information sent along afferent pathway to control center. Receptor Control Center BALANCE Afferent pathway IMBALANCE 1 2 3

Components of a Control Mechanism Stimulus produces change in variable. Receptor detects change. Input: Information sent along afferent pathway to control center. Output: Information sent along efferent pathway to effector. Receptor Effector Control Center BALANCE Afferent pathway Efferent pathway IMBALANCE 1 2 3 4

Components of a Control Mechanism Stimulus produces change in variable. Receptor detects change. Input: Information sent along afferent pathway to control center. Output: Information sent along efferent pathway to effector. Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level. Receptor Effector Control Center BALANCE Afferent pathway Efferent pathway IMBALANCE 1 2 3 4 5

Negative Feedback The response reduces or shuts off the original stimulus Example: Regulation of body temperature (a nervous mechanism)

Negative Feedback Stimulus Sweat glands activated Shivering begins Body temperature rises BALANCE Information sent along the afferent pathway to control center Afferent pathway Efferent along the efferent pathway to effectors pathway to effectors Body temperature falls Receptors Temperature-sensitive cells in skin and brain Effectors Sweat glands Skeletal muscles Control Center (thermoregulatory center in brain) Response Evaporation of sweat Body temperature falls; stimulus ends Body temperature rises;

Positive Feedback The response enhances or exaggerates the original stimulus May exhibit a cascade or amplifying effect Usually controls infrequent events Enhancement of labor contractions by oxytocin Platelet plug formation and blood clotting

Positive Feedback 1 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. 1

Positive Feedback 1 2 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. 1 2

Positive Feedback 1 3 2 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. Positive feedback loop Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. Released chemicals attract more platelets. 1 2 3

Positive Feedback 1 3 2 4 Break or tear occurs in blood vessel wall. Feedback cycle ends when plug is formed. Positive feedback cycle is initiated. Positive feedback loop Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. Released chemicals attract more platelets. Platelet plug forms. 1 2 3 4

Homeostatic Imbalance Disturbance of homeostasis Increases risk of disease Contributes to changes associated with aging May allow destructive positive feedback mechanisms to take over (heart failure)

The Language of Anatomy Anatomical Position Body Landmarks Directional Terms Regional Terms Body Planes and Sections Body Cavities and Membranes

Body Landmarks Cervical Anterior/Ventral Pubic (genital) Cephalic Frontal Orbital Nasal Oral Mental Thoracic Axillary Mammary Sternal Abdominal Umbilical Pelvic Inguinal (groin) Upper limb Acromial Brachial (arm) Antecubital Antebrachial (forearm) Carpal (wrist) Manus (hand) Palmar Pollex Digital Lower limb Coxal (hip) Femoral (thigh) Patellar Crural (leg) Fibular or peroneal Pedal (foot) Tarsal (ankle) Metatarsal Hallux Thorax Abdomen Back (Dorsum)

Body Landmarks Cervical Back (dorsal) Posterior/Dorsal Scapular Vertebral Lumbar Sacral Gluteal Perineal (between anus and external genitalia) Upper limb Acromial Brachial (arm) Olecranal Antebrachial (forearm) Manus (hand) Metacarpal Digital Lower limb Femoral (thigh) Popliteal Sural (calf) Fibular or peroneal Pedal (foot) Calcaneal Plantar Cephalic Otic Occipital (back of head) Thorax Abdomen Back (Dorsum)

Body Planes and Sections Transverse plane Median (midsagittal) plane Frontal plane Liver Spleen Pancreas Aorta Vertebral column Spinal cord Subcutaneous fat layer Body wall Rectum Intestines Left and right lungs Heart Stomach Arm (a) Frontal section (through torso) (b) Transverse section (through torso, inferior view) (c) Median section (midsagittal)

Body Cavities Cranial cavity (contains brain) Dorsal body Vertebral spinal cord) Superior mediastinum Pericardial cavity within the mediastinum Pleural Abdomino- pelvic Ventral body (thoracic and abdominopelvic cavities) Abdominal cavity (contains digestive viscera) Diaphragm Pelvic cavity (contains urinary bladder, reproductive organs, and rectum) Thoracic heart and lungs) Lateral view Anterior view Dorsal body cavity Ventral body cavity