Chapter 1 The Human Body: An Orientation: Part A Overview of Anatomy and Physiology O Anatomy: The study of structure O Subdivisions: O Gross or macroscopic (e.g., regional, surface, and systemic anatomy) O Microscopic (e.g., cytology and histology) O Developmental (e.g., embryology) Overview of Anatomy and Physiology O Essential tools for the study of anatomy: O Mastery of anatomical terminology O Observation O Manipulation O Palpation O Auscultation Overview of Anatomy and Physiology O Physiology: The study of function at many levels O Subdivisions are based on organ systems (e.g., renal or cardiovascular physiology) Overview of Anatomy and Physiology O Essential tools for the study of physiology: O Ability to focus at many levels (from systemic to cellular and molecular) O Basic physical principles (e.g., electrical currents, pressure, and movement) O Basic chemical principles Principle of Complementarity O Anatomy and physiology are inseparable. O Function always reflects structure O What a structure can do depends on its specific form Levels of Structural Organization O Chemical: atoms and molecules (Chapter 2) O Cellular: cells and their organelles (Chapter 3) O Tissue: groups of similar cells (Chapter 4) O Organ: contains two or more types of tissues O Organ system: organs that work closely together O Organismal: all organ systems Copyright 2010 Pearson Education, Inc. Cardiovascular system 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 Connective tissue Blood vessel (organ) Heart Blood vessels Epithelial tissue Smooth muscle tissue Figure 1.1 Copyright 2010 Pearson Education, Inc. Molecule Atoms Chemical level Atoms combine to form molecules. 1 Figure 1.1, step 1 Copyright 2010 Pearson Education, Inc. Organelle Molecule Atoms Chemical level Atoms combine to form molecules. Cellular level Cells are made up of molecules. Smooth muscle cell 1 2 Figure 1.1, step 2 Copyright 2010 Pearson Education, Inc. 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. Smooth muscle cell Smooth muscle tissue Figure 1.1, step 3 Copyright 2010 Pearson Education, Inc. 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. Smooth muscle cell Smooth muscle tissue Connective tissue Blood vessel (organ) Epithelial tissue Smooth muscle tissue Figure 1.1, step 4 Copyright 2010 Pearson Education, Inc. Cardiovascular system 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. Smooth muscle cell Smooth muscle tissue Connective tissue Blood vessel (organ) Heart Blood vessels Epithelial tissue Smooth muscle tissue Figure 1.1, step 5 Copyright 2010 Pearson Education, Inc. Cardiovascular system 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 Connective tissue Blood vessel (organ) Heart Blood vessels Epithelial tissue Smooth muscle tissue Figure 1.1, step 6 Overview of Organ Systems O Note major organs and functions of the 11 organ systems (Fig. 1.3) Copyright 2010 Pearson Education, Inc. Figure 1.3a Nails Skin Hair (a) Integumentary System Forms the external body covering, and protects deeper tissues from injury. Synthesizes vitamin D, and houses cutaneous (pain, pressure, etc.) receptors and sweat and oil glands. Copyright 2010 Pearson Education, Inc. Figure 1.3b Bones Joint (b) Skeletal System Protects and supports body organs, and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals. Copyright 2010 Pearson Education, Inc. Figure 1.3c Skeletal muscles (c) Muscular System Allows manipulation of the environment, locomotion, and facial expression. Main- tains posture, and produces heat. Copyright 2010 Pearson Education, Inc. Figure 1.3d Brain Nerves Spinal cord (d) Nervous System As the fast-acting control system of the body, it responds to internal and external changes by activating appropriate muscles and glands. Copyright 2010 Pearson Education, Inc. Figure 1.3e Pineal gland Pituitary gland Thyroid gland Thymus Adrenal gland Pancreas Testis Ovary (e) Endocrine System Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells. Copyright 2010 Pearson Education, Inc. Figure 1.3f (f) Cardiovascular System Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood. Heart Blood vessels Copyright 2010 Pearson Education, Inc. Figure 1.3g Lymphatic vessels Red bone marrow Thoracic duct Thymus Spleen Lymph nodes (g) 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. The immune response mounts the attack against foreign substances within the body. Copyright 2010 Pearson Education, Inc. Figure 1.3h Nasal cavity Bronchus Pharynx Larynx Trachea Lung (h) Respiratory System Keeps blood constantly supplied with oxygen and removes carbon dioxide. The gaseous exchanges occur through the walls of the air sacs of the lungs. Copyright 2010 Pearson Education, Inc. Figure 1.3i Liver Oral cavity Esophagus Large intestine Stomach Small intestine Rectum Anus (i) Digestive System Breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces. Copyright 2010 Pearson Education, Inc. Figure 1.3j Kidney Ureter Urinary bladder Urethra (j) Urinary System Eliminates nitrogenous wastes from the body. Regulates water, electrolyte and acid-base balance of the blood. Copyright 2010 Pearson Education, Inc. Figure 1.3k-l Prostate gland Ductus deferens Penis Testis Scrotum Ovary Uterine tube Mammary glands (in breasts) Uterus Vagina Overall function is production of offspring. Testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones. The remaining female structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn. (k) Male Reproductive System (l) Female Reproductive System Organ Systems Interrelationships O All cells depend on organ systems to meet their survival needs O Organ systems work cooperatively to perform necessary life functions Copyright 2010 Pearson Education, Inc. Figure 1.2 Digestive system Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces) Respiratory system Takes in oxygen and eliminates carbon dioxide Food O2O2 CO 2 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 CO 2 O2O2 Necessary Life Functions 1. Maintaining boundaries between internal and external environments O Plasma membranes O Skin 2. Movement (contractility) O Of body parts (skeletal muscle) O Of substances (cardiac and smooth muscle) Necessary Life Functions 3. Responsiveness: The ability to sense and respond to stimuli O Withdrawal reflex O Control of breathing rate 4. Digestion O Breakdown of ingested foodstuffs O Absorption of simple molecules into blood Necessary Life Functions 5. Metabolism: All chemical reactions that occur in body cells O Catabolism and anabolism 6. Excretion: The removal of wastes from metabolism and digestion O Urea, carbon dioxide, feces Necessary Life Functions 7. Reproduction O Cellular division for growth or repair O Production of offspring 8. Growth: Increase in size of a body part or of organism Survival Needs 1. Nutrients O Chemicals for energy and cell building O Carbohydrates, fats, proteins, minerals, vitamins 2. Oxygen O Essential for energy release (ATP production) Survival Needs 3. Water O Most abundant chemical in the body O Site of chemical reactions 4. Normal body temperature O Affects rate of chemical reactions 5. Appropriate atmospheric pressure O For adequate breathing and gas exchange in the lungs Homeostasis O Maintenance of a relatively stable internal environment despite continuous outside changes O A dynamic state of equilibrium Homeostatic Control Mechanisms O Involve continuous monitoring and regulation of many factors (variables) O Nervous and endocrine systems accomplish the communication via nerve impulses and hormones Components of a Control Mechanism 1. Receptor (sensor) O Monitors the environment O Responds to stimuli (changes in controlled variables) 2. Control center O Determines the set point at which the variable is maintained O Receives input from receptor O Determines appropriate response Components of a Control Mechanism 3. Effector O Receives output from control center O Provides the means to respond O Response acts to reduce or enhance the stimulus (feedback) Copyright 2010 Pearson Education, Inc. 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. ReceptorEffector Control Center BALANCE Afferent pathway Efferent pathway IMBALANCE Figure 1.4 Copyright 2010 Pearson Education, Inc. Stimulus produces change in variable. BALANCE IMBALANCE 1 Figure 1.4, step 1 Copyright 2010 Pearson Education, Inc. Stimulus produces change in variable. Receptor detects change. Receptor BALANCE IMBALANCE 1 2 Figure 1.4, step 2 Copyright 2010 Pearson Education, Inc. Stimulus produces change in variable. Receptor detects change. Input: Information sent along afferent pathway to control center. Receptor Control Center BALANCE Afferent pathway IMBALANCE Figure 1.4, step 3 Copyright 2010 Pearson Education, Inc. 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. ReceptorEffector Control Center BALANCE Afferent pathway Efferent pathway IMBALANCE Figure 1.4, step 4 Copyright 2010 Pearson Education, Inc. 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. ReceptorEffector Control Center BALANCE Afferent pathway Efferent pathway IMBALANCE Figure 1.4, step 5 Negative Feedback O The response reduces or shuts off the original stimulus O Examples: O Regulation of body temperature (a nervous mechanism) O Regulation of blood volume by ADH (an endocrine mechanism) Copyright 2010 Pearson Education, Inc. Figure 1.5 Sweat glands activated Shivering begins Stimulus Body temperature rises BALANCE Information sent along the afferent pathway to control center Information sent along the afferent pathway to control center Afferent pathway Afferent pathway Efferent pathway Efferent pathway Information sent along the efferent pathway to effectors Information sent along the efferent pathway to effectors Stimulus Body temperature falls Receptors Temperature-sensitive cells in skin and brain Receptors Temperature-sensitive cells in skin and brain Effectors Sweat glands Effectors Skeletal muscles Control Center (thermoregulatory center in brain) Control Center (thermoregulatory center in brain) Response Evaporation of sweat Body temperature falls; stimulus ends Response Body temperature rises; stimulus ends Negative Feedback: Regulation of Blood Volume by ADH O Receptors sense decreased blood volume O Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH) O ADH causes the kidneys (effectors) to return more water to the blood Positive Feedback O The response enhances or exaggerates the original stimulus O May exhibit a cascade or amplifying effect O Usually controls infrequent events e.g.: O Enhancement of labor contractions by oxytocin (Chapter 28) O Platelet plug formation and blood clotting Copyright 2010 Pearson Education, Inc. 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 Figure 1.6 Copyright 2010 Pearson Education, Inc. Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. 1 Figure 1.6, step 1 Copyright 2010 Pearson Education, Inc. Positive feedback cycle is initiated. Break or tear occurs in blood vessel wall. Platelets adhere to site and release chemicals. 1 2 Figure 1.6, step 2 Copyright 2010 Pearson Education, Inc. 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 Figure 1.6, step 3 Copyright 2010 Pearson Education, Inc. 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 Figure 1.6, step 4 Homeostatic Imbalance O Disturbance of homeostasis O Increases risk of disease O Contributes to changes associated with aging O May allow destructive positive feedback mechanisms to take over (e.g., heart failure)