The Human Body: An Orientation: Part A

PowerPoint Lecture Slides prepared by Janice Meeking, Mount Royal College C H A P T E R 1 The Human Body: An Orientation: Part A

Overview of Anatomy and Physiology Anatomy: The study of structure Subdivisions: Gross or macroscopic (e.g., regional, surface, and systemic anatomy) Microscopic (e.g., cytology and histology) Developmental (e.g., embryology)

Overview of Anatomy and Physiology Essential tools for the study of anatomy: Mastery of anatomical terminology Observation Manipulation Palpation Auscultation

Overview of Anatomy and Physiology Physiology: The study of function at many levels Subdivisions are based on organ systems (e.g., renal or cardiovascular physiology)

Overview of Anatomy and Physiology Essential tools for the study of physiology: Ability to focus at many levels (from systemic to cellular and molecular) Basic physical principles (e.g., electrical currents, pressure, and movement) Basic chemical principles

Principle of Complementarity Anatomy and physiology are inseparable. Function always reflects structure What a structure can do depends on its specific form

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

Atoms Molecule Organelle Smooth muscle cell 1 Chemical level Atoms combine to form molecules. 2 Cellular level Cells are made up of molecules. Smooth muscle tissue Cardiovascular system Heart Blood vessels 3 Tissue level Tissues consist of similar types of cells. Blood vessel (organ) Smooth muscle tissue Connective tissue Epithelial tissue 4 Organ level Organs are made up of different types of tissues. 6 Organismal level The human organism is made up of many organ systems. 5 Organ system level Organ systems consist of different organs that work together closely. Figure 1.1

Atoms Molecule 1 Chemical level Atoms combine to form molecules. Figure 1.1, step 1

Atoms Molecule Organelle Smooth muscle cell 1 Chemical level Atoms combine to form molecules. 2 Cellular level Cells are made up of molecules. Figure 1.1, step 2

Atoms Molecule Organelle Smooth muscle cell 1 Chemical level Atoms combine to form molecules. 2 Cellular level Cells are made up of molecules. Smooth muscle tissue 3 Tissue level Tissues consist of similar types of cells. Blood vessel (organ) Smooth muscle tissue Connective tissue Epithelial tissue 4 Organ level Organs are made up of different types of tissues. Figure 1.1, step 4

Atoms Molecule Organelle Smooth muscle cell 1 Chemical level Atoms combine to form molecules. 2 Cellular level Cells are made up of molecules. Smooth muscle tissue Cardiovascular system Heart Blood vessels 3 Tissue level Tissues consist of similar types of cells. Blood vessel (organ) Smooth muscle tissue Connective tissue Epithelial tissue 4 Organ level Organs are made up of different types of tissues. 5 Organ system level Organ systems consist of different organs that work together closely. Figure 1.1, step 5

Overview of Organ Systems Note major organs and functions of the 11 organ systems (Fig. 1.3)

Hair Skin Nails (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. Figure 1.3a

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. Figure 1.3b

Skeletal muscles (c) Muscular System Allows manipulation of the environment, locomotion, and facial expression. Maintains posture, and produces heat. Figure 1.3c

Brain Spinal cord Nerves (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. Figure 1.3d

Pineal gland Thyroid gland Thymus Pituitary gland 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. Figure 1.3e

Heart Blood vessels (f) Cardiovascular System Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood. Figure 1.3f

Red bone marrow Thymus Lymphatic vessels Thoracic duct 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. Figure 1.3g

Nasal cavity Pharynx Larynx Trachea Bronchus 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. Figure 1.3h

Oral cavity Esophagus Liver Stomach Small intestine Large 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. Figure 1.3i

Kidney Ureter Urinary bladder Urethra (j) Urinary System Eliminates nitrogenous wastes from the body. Regulates water, electrolyte and acid-base balance of the blood. Figure 1.3j

Mammary glands (in breasts) Prostate gland Ovary Penis Testis Scrotum Ductus deferens Uterus Vagina Uterine tube (k) Male Reproductive System (l) Female Reproductive System 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. Figure 1.3k-l

Organ Systems Interrelationships All cells depend on organ systems to meet their survival needs Organ systems work cooperatively to perform necessary life functions

Digestive system Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces) Respiratory system Takes in oxygen and eliminates carbon dioxide Food O 2 CO 2 Cardiovascular system Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs Blood CO 2 O 2 Nutrients Heart Interstitial fluid Urinary system Eliminates nitrogenous wastes and excess ions Nutrients and wastes pass between blood and cells via the interstitial fluid Feces Integumentary system Protects the body as a whole from the external environment Urine Figure 1.2

Necessary Life Functions 1. Maintaining boundaries between internal and external environments Plasma membranes Skin 2. Movement (contractility) Of body parts (skeletal muscle) Of substances (cardiac and smooth muscle)

Necessary Life Functions 3. Responsiveness: The ability to sense and respond to stimuli Withdrawal reflex Control of breathing rate 4. Digestion Breakdown of ingested foodstuffs Absorption of simple molecules into blood

Necessary Life Functions 5. Metabolism: All chemical reactions that occur in body cells Catabolism and anabolism 6. Excretion: The removal of wastes from metabolism and digestion Urea, carbon dioxide, feces

Necessary Life Functions 7. Reproduction Cellular division for growth or repair Production of offspring 8. Growth: Increase in size of a body part or of organism

Survival Needs 1. Nutrients Chemicals for energy and cell building Carbohydrates, fats, proteins, minerals, vitamins 2. Oxygen Essential for energy release (ATP production)

Survival Needs 3. Water Most abundant chemical in the body Site of chemical reactions 4. Normal body temperature Affects rate of chemical reactions 5. Appropriate atmospheric pressure For adequate breathing and gas exchange in the lungs

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 (variables) Nervous and endocrine systems accomplish the communication via nerve impulses and hormones

Components of a Control Mechanism 1. Receptor (sensor) Monitors the environment Responds to stimuli (changes in controlled variables) 2. Control center Determines the set point at which the variable is maintained Receives input from receptor Determines appropriate response

Components of a Control Mechanism 3. Effector Receives output from control center Provides the means to respond Response acts to reduce or enhance the stimulus (feedback)

3 Input: Information sent along afferent pathway to control center. Afferent 2 pathway Receptor Receptor detects change. 1 Stimulus produces change in variable. Control Center BALANCE Efferent pathway 4 Output: Information sent along efferent pathway to effector. Effector 5 Response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level. Figure 1.4

1 Stimulus produces change in variable. BALANCE Figure 1.4, step 1

2 Receptor detects change. 1 Stimulus produces change in variable. Receptor BALANCE Figure 1.4, step 2

3 Input: Information sent along afferent Control pathway to control Center center. Afferent 2 pathway Receptor Receptor detects change. 1 Stimulus produces change in variable. BALANCE Figure 1.4, step 3

Negative Feedback The response reduces or shuts off the original stimulus Examples: Regulation of body temperature (a nervous mechanism) Regulation of blood volume by ADH (an endocrine mechanism)

Stimulus Body temperature rises Information sent along the afferent pathway to control center Receptors Temperature-sensitive cells in skin and brain Control Center (thermoregulatory center in brain) Afferent pathway BALANCE Efferent pathway Information sent along the efferent pathway to effectors Effectors Sweat glands Sweat glands activated Response Evaporation of sweat Body temperature falls; stimulus ends Response Body temperature rises; stimulus ends Stimulus Body temperature falls Effectors Skeletal muscles Receptors Temperature-sensitive cells in skin and brain Shivering begins Information sent along the efferent pathway to effectors Efferent pathway Control Center (thermoregulatory center in brain) Afferent pathway Information sent along the afferent pathway to control center Figure 1.5

Negative Feedback: Regulation of Blood Volume by ADH Receptors sense decreased blood volume Control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH) ADH causes the kidneys (effectors) to return more water to the blood

Positive Feedback The response enhances or exaggerates the original stimulus May exhibit a cascade or amplifying effect Usually controls infrequent events e.g.: Enhancement of labor contractions by oxytocin (Chapter 28) Platelet plug formation and blood clotting

1 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. 3 Released chemicals attract more platelets. Positive feedback loop 2 Platelets adhere to site and release chemicals. Feedback cycle ends when plug is formed. 4 Platelet plug forms. Figure 1.6

1 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. Figure 1.6, step 1

1 Break or tear occurs in blood vessel wall. Positive feedback cycle is initiated. 2 Platelets adhere to site and release chemicals. Figure 1.6, step 2

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

PowerPoint Lecture Slides prepared by Janice Meeking, Mount Royal College C H A P T E R 1 The Human Body: An Orientation: Part B

Anatomical Position Standard anatomical body position: Body erect Feet slightly apart Palms facing forward

Cephalic Frontal Orbital Nasal Oral Mental Cervical Thoracic Axillary Mammary Sternal Abdominal Umbilical Pelvic Inguinal (groin) Pubic (genital) Thorax Abdomen Back (Dorsum) (a) Anterior/Ventral 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 Digital Hallux Figure 1.7a

Table 1.1

Regional Terms Two major divisions of body: Axial Head, neck, and trunk Appendicular Limbs Regional terms designate specific areas

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 (b) Posterior/Dorsal Cephalic Otic Occipital (back of head) Cervical Back (dorsal) Scapular Vertebral Lumbar Sacral Gluteal Perineal (between anus and external genitalia) Thorax Abdomen Back (Dorsum) Figure 1.7b

Body Planes Plane: Flat surface along which body or structure is cut for anatomical study

Body Planes Sagittal plane Divides body vertically into right and left parts Produces a sagittal section Midsagittal (median) plane Lies on midline Parasagittal plane Not on midline

Body Planes Frontal (coronal) plane Divides body vertically into anterior and posterior parts Transverse (horizontal) plane Divides body horizontally into superior and inferior parts Produces a cross section Oblique section Cuts made diagonally

Frontal plane Median (midsagittal) plane Transverse plane (a) Frontal section (through torso) (b) Transverse section (through torso, inferior view) Pancreas (c) Median section (midsagittal) Aorta Spleen Left and Liver right lungs Heart Spleen Stomach Arm Liver Spinal cord Vertebral Subcutaneous fat layer Body wall Rectum Intestines column Figure 1.8

Anatomical Variability Over 90% of all anatomical structures match textbook descriptions, but: Nerves or blood vessels may be somewhat out of place Small muscles may be missing

Body Cavities Dorsal cavity Protects nervous system Two subdivisions: Cranial cavity Encases brain Vertebral cavity Encases spinal cord

Body Cavities Ventral cavity Houses internal organs (viscera) Two subdivisions (separated by diaphragm): Thoracic cavity Abdominopelvic cavity

Dorsal body cavity Cranial cavity (contains brain) Vertebral cavity (contains spinal cord) (a) Lateral view Cranial cavity Vertebral cavity Superior Thoracic mediastinum cavity Pleural (contains cavity heart and Pericardial lungs) cavity within the mediastinum Diaphragm Abdominal cavity (contains digestive viscera) Pelvic cavity (contains urinary bladder, reproductive organs, and rectum) (b) Anterior view Abdominopelvic cavity Dorsal body cavity Ventral body cavity Ventral body cavity (thoracic and abdominopelvic cavities) Figure 1.9a-b

Ventral Body Cavities Thoracic cavity subdivisions: Two pleural cavities Each houses a lung Mediastinum Contains pericardial cavity Surrounds thoracic organs Pericardial cavity Encloses heart

Ventral Body Cavities Abdominopelvic cavity subdivisions: Abdominal cavity Contains stomach, intestines, spleen, and liver Pelvic cavity Contains urinary bladder, reproductive organs, and rectum

Serous Membrane (Serosa) Thin, double-layered membrane separated by serous fluid Parietal serosa lines internal body walls Visceral serosa covers the internal organs

Outer balloon wall (comparable to parietal serosa) Air (comparable to serous cavity) Inner balloon wall (comparable to visceral serosa) Heart Parietal pericardium Pericardial space with serous fluid Visceral pericardium (b) The serosae associated with the heart. Figure 1.10a-b

Abdominopelvic Regions Nine divisions used primarily by anatomists

Right upper quadrant (RUQ) Right lower quadrant (RLQ) Left upper quadrant (LUQ) Left lower quadrant (LLQ) Figure 1.11

Abdominopelvic Quadrants Divisions used primarily by medical personnel

Right hypochondriac region Epigastric region Left hypochondriac region Liver Gallbladder Diaphragm Stomach Right lumbar region Right iliac (inguinal) region Umbilical region Hypogastric (pubic) region Left lumbar region Left iliac (inguinal) region Ascending colon of large intestine Small intestine Cecum Appendix Transverse colon of large intestine Descending colon of large intestine Initial part of sigmoid colon Urinary bladder (a) Nine regions delineated by four planes (b) Anterior view of the nine regions showing the superficial organs Figure 1.12

Other Body Cavities Oral and digestive cavities Nasal cavity Orbital cavities Middle ear cavities Synovial cavities