Chapter 1 Notes - Fundamentals of Anatomy & Physiology

Anatomy and Physiology: Key Concepts

• Anatomy and Physiology definitions

  • Anatomy describes the structures of the body: what they are made of, where they are located, and associated structures.

  • Physiology is the study of functions of anatomical structures, including individual and cooperative functions.

  • Human anatomy focuses on levels from gross (macroscopic) to microscopic (cells and molecules):

  • Gross anatomy: surface anatomy, regional anatomy, sectional anatomy, systemic anatomy, clinical anatomy, developmental anatomy (embryology).

  • Microscopic anatomy: cytology (cells), histology (tissues).

• Subfields of physiology

  • Cell physiology: functions of cells

  • Organ physiology: functions of specific organs

  • Systemic physiology: functions of organ systems

  • Pathological physiology: effects of diseases on organs or systems

• Patient presentation and diagnosis (scientific method)

  • Signs: objective evidence (e.g., fever)

  • Symptoms: subjective experiences (e.g., tiredness)

  • Physicians form a hypothesis and test it by collecting and analyzing data to reach a diagnosis.

Levels of Organization

• Chemical level

  • Atoms are the smallest stable units of matter

  • Molecules are groups of atoms bonded together

• Cellular level

  • Cells are the smallest living units

• Tissue level

  • Tissues are groups of cells working together

• Organ level

  • Organs are made of two or more tissues working together

• Organ system level

  • An organ system is a group of interacting organs

  • Humans have $11$ organ systems

• Organism level

  • An individual life form (human) is an organism

Figure reference: Levels of Organization illustrate progression from chemical level to organism.

The Organ Systems

• Integumentary system

  • Major organs: skin, hair, sweat glands, nails

  • Functions: protects against environmental hazards; helps regulate body temperature; provides sensory information

• Skeletal system

  • Major organs: bones, cartilages, associated ligaments, bone marrow

  • Functions: provides support and protection for other tissues; stores calcium and other minerals; forms blood cells

• Muscular system

  • Major organs: skeletal muscles and associated tendons

  • Functions: provides movement; protection and support for other tissues; generates heat to maintain body temperature

• Nervous system

  • Major organs: brain, spinal cord, peripheral nerves, sense organs

  • Functions: directs immediate responses to stimuli; coordinates or moderates activities of other organ systems; provides and interprets sensory information about external conditions

• Endocrine system

  • Major organs: pituitary gland, thyroid gland, pancreas, adrenal glands, gonads, endocrine tissues in other systems

  • Functions: directs long-term changes in activities of other organ systems; adjusts metabolic activity and energy use; controls structural and functional changes during development

• Cardiovascular system

  • Major organs: heart, blood, blood vessels

  • Functions: distributes blood cells, water, nutrients, waste products, oxygen, carbon dioxide; distributes heat and assists in control of body temperature

• Lymphatic system

  • Major organs: spleen, thymus, lymphatic vessels, lymph nodes, tonsils

  • Functions: defends against infection and disease; returns tissue fluids to the bloodstream

• Respiratory system

  • Major organs: nasal cavities, sinuses, larynx, trachea, bronchi, lungs, alveoli

  • Functions: delivers air to alveoli; provides oxygen to the bloodstream; removes carbon dioxide from the bloodstream; produces sounds for communication

• Digestive system

  • Major organs: teeth, tongue, pharynx, esophagus, stomach, small intestine, large intestine, liver, gallbladder, pancreas

  • Functions: processes and digests food; absorbs and conserves water; absorbs nutrients; stores energy reserves

• Urinary system

  • Major organs: kidneys, ureters, urinary bladder, urethra

  • Functions: excretes waste products from the blood; controls water balance by regulating urine volume; stores urine prior to voluntary elimination; regulates blood ion concentrations and pH

• Male reproductive system

  • Major organs: testes, epididymides, ductus deferentia, seminal vesicles, prostate gland, penis, scrotum

  • Functions: produces male sex cells (sperm), seminal fluids, and hormones; sexual intercourse

• Female reproductive system

  • Major organs: ovaries, uterine tubes, uterus, vagina, labia, clitoris, mammary glands

  • Functions: produces female sex cells (oocytes) and hormones; supports developing embryo from conception to delivery; provides milk to nourish newborn; sexual intercourse

Body Cavities

• Essential functions of body cavities

  • Protect organs from shocks and impacts

  • Permit significant changes in size and shape of internal organs

• Ventral body cavity (coelom)

  • Divided by the diaphragm into the thoracic cavity and the abdominopelvic cavity

• Contents

  • Body cavities contain viscera (internal organs)

Serous Membranes (Serosa)

• Serous membrane lines body cavities and covers organs

• Composed of parietal and visceral layers

  • Parietal serosa lines the cavity

  • Visceral serosa covers the organ

Thoracic Cavity

• Right and left pleural cavities contain the lungs

• Mediastinum (upper portion contains blood vessels, trachea, esophagus, thymus; lower portion contains the pericardial cavity)

• The heart is located within the pericardial cavity

Figure references (relationships): Subdivisions of the body cavities of the trunk show that the diaphragm divides the thoracic cavity from the abdominopelvic cavity, with the pericardial and pleural cavities within the thoracic region.

Abdominopelvic Cavity

• Peritoneal cavity is a chamber within the abdominopelvic cavity

  • Parietal peritoneum lines the internal body wall

  • Visceral peritoneum covers the organs

• Abdominal cavity (superior portion)

  • Contains digestive organs

  • Retroperitoneal space lies posterior to peritoneum and anterior to the muscular body wall (e.g., pancreas, kidneys, ureters, parts of digestive tract)

• Pelvic cavity (inferior portion)

  • Medial to pelvic bones

  • Contains reproductive organs, rectum, and bladder

Homeostasis and Regulation

• Homeostasis

  • All body systems work together to maintain a stable internal environment

  • Systems respond to external and internal changes to keep variables within normal ranges (e.g., body temperature, fluid balance)

• Homeostatic regulation

  • Autoregulation: automatic response of a cell, tissue, or organ to an environmental change

  • Extrinsic regulation: responses controlled by nervous and endocrine systems

• Homeostatic reflex mechanism

  • Receptor: receives the stimulus

  • Control center: processes the signal and sends instructions

  • Effector: carries out instructions

• Goal

  • Limit fluctuations of internal conditions to keep them close to a set point

Negative and Positive Feedback

• Negative feedback

  • The effector's response negates the stimulus

  • Restores homeostasis and maintains normal range

  • Example: regulation of body temperature; when temperature rises, mechanisms are activated to cool the body; when it falls, mechanisms warm it

  Example figures:

  • Control of room temperature (Fig. 1–8): set point around 22°C; thermostat (control center) triggers heater or AC (effectors) to restore normal temperature

  • Control of body temperature (Fig. 1–9): hypothalamus acts as thermoregulatory center; vessels and sweat glands adjust to keep body temperature within a normal range $ext{approximately } 36.7^<br>0 ext{C} ext{ to } 37.2^<br>0 ext{C}$

• Positive feedback

  • Initial stimulus amplifies the original change in conditions

  • Moves away from homeostasis; normal range is not maintained

  • Purpose: rapidly complete a process to reestablish homeostasis in certain contexts

  Example: Blood clotting (Fig. 1–10): clotting chemicals amplify the process until a clot forms to seal the vessel

Systems Integration and Homeostasis

• Systems work together to maintain homeostasis

• Homeostasis is a state of dynamic equilibrium

  • Opposition forces are balanced

  • Dynamic equilibrium: continual adaptation to changing conditions

• Physiological systems work to maintain balance; failure results in disease

Anatomical Terminology and Landmarks

• Medical terminology overview

  • Terms related to the body in health and disease

  • Most commemorative names (eponyms) have been replaced by precise terms

• Anatomical terminology basics

  • Surface anatomy: locating structures on or near the body surface

  • Anatomical position: feet together, arms at sides, palms facing forward

  • Supine: lying face up; Prone: lying face down

Anatomical Landmarks (selected highlights from Fig. 1–3a and Fig. 1–3b)

• Anterior view (frontal)

  • Frontal (forehead)

  • Nasal (nose)

  • Ocular / Orbital (eye)

  • Cranial (skull)

  • Cephalic (head)

  • Facial (face)

  • Otic (ear)

  • Buccal (cheek)

  • Cervical (neck)

  • Thoracic (thorax, chest)

  • Mammary (breast)

  • Abdominal (abdomen)

  • Umbilical (navel)

  • Trunk

  • Oral (mouth)

  • Mental (chin)

  • Axillary (armpit)

  • Brachial (arm)

  • Antecubital (front of elbow)

• Forelimb and lower limb landmarks

  • Antebrachial (forearm)

  • Carpal (wrist)

  • Palmar (palm)

  • Pelvic (pelvis)

  • Manual (hand)

  • Pollex (thumb)

  • Digits (fingers)

  • Inguinal (groin)

  • Pubic (pubis)

  • Femoral (thigh)

  • Patellar (kneecap)

  • Crural (leg)

  • Tarsal (ankle)

  • Digits (toes)

  • Hallux (great toe)

  • Pedal (foot)

• Posterior view landmarks

  • Cephalic (head)

  • Acromial (shoulder)

  • Dorsal (back)

  • Cervical (neck)

  • Olecranal (back of elbow)

  • Lumbar (loin)

  • Gluteal (buttock)

  • Popliteal (back of knee)

  • Sural (calf)

  • Calcaneal (heel of foot)

  • Plantar (sole of foot)

Anatomical Regions, Directions, and Planes

• Anatomical regions

  • Abdominopelvic quadrants: RUQ, RLQ, LUQ, LLQ

  • Abdominopelvic regions: Right hypochondriac, Epigastric, Umbilical, Hypogastric (pubic), Left hypochondriac, Right lumbar, Right inguinal, Left lumbar, Left inguinal

• Anatomical directions (reference terms)

  • Superior (toward the head) / Cranial or Cephalic

  • Inferior (toward the feet) / Caudal

  • Anterior (toward the front) / Ventral

  • Posterior (toward the back) / Dorsal

  • Medial (toward the midline) / Lateral (away from the midline)

  • Proximal (toward the point of attachment) / Distal (away from the point of attachment)

  • Superficial (toward the body surface) / Deep (toward the interior)

• Sectional anatomy and planes

  • Section: a slice through a 3D object; used to visualize internal organization and for radiologic techniques (MRI, PET, CT)

  • Sectional plane: a single view along a 2D flat surface

  • Frontal (coronal) plane: divides the body into anterior and posterior portions; a frontal section

  • Sagittal plane: divides body into left and right portions; midsagittal plane passes through the midline; parasagittal plane is offset from the midline

  • Transverse (horizontal) plane: divides the body into superior and inferior portions

• Orientation notes for radiologic sections

  • In clinical images, transverse sections are often shown as if standing at the feet looking toward the head

Sectional Planes (summary of Fig. 1–6)

• Frontal (coronal) plane

  • Divides anterior vs. posterior

  • Frontal sections commonly through the skull

• Sagittal plane

  • Divides right vs. left

  • Midsagittal: equal left and right halves

  • Parasagittal: unequal left and right portions

• Transverse (horizontal) plane

  • Divides superior vs. inferior portions

Review of Key Values and Notable Facts

• Number of organ systems in humans: $11$

• Normal human body temperature set point: $37^ op{}^ op ext{C}$ (thermoregulation) • Typical resting range: $36.7^ op{}^ op ext{C} ext{ to } 37.2^ op{}^ op ext{C}$

• Room temperature example in regulatory physiology: $22^ op{}^ op ext{C}$ as a set point in a room-temperature control model

• The diaphragm divides the ventral body cavity into thoracic and abdominopelvic cavities

This set of notes is designed to mimic a full, well-organized study guide, capturing definitions, hierarchical structure, organ systems with examples, body cavities and membranes, anatomical terminology and landmarks, directional references and planes, sectional anatomy, and the core concepts of homeostasis and feedback mechanisms as presented in the provided transcript.