Chapter 1: An Introduction to Anatomy & Physiology

Anatomy

the study of internal and external body structures and their physical relationships among other body parts

Physiology

the study of how living organisms perform their vital functions

The Principle of Complementarity of Structure and Function

all specific functions are performed by specific structures, and the form of a structure relates to its function

Gross/Macroscopic Anatomy

examines large structures; visible to naked eye

Microscopic Anatomy

examines structures only visible w/ magnification, such as cells and molecules

Types of Gross Anatomy

Surface, regional, sectional, systemic, clinical, developmental

Surface Anatomy

body surface

Regional Anatomy

specific body areas

Sectional Anatomy

understanding relationship of body structures by examining a cross section 

Systemic Anatomy 

organ systems

Clinical Anatomy

as used in clinical practice, includes pathological and radiological anatomy

Pathological Anatomy

anatomical changes during illness

Radiological Anatomy

anatomical structures seen using imaging techniques

Surgical Anatomy 

anatomical landmarks important during surgery

Developmental Anatomy 

structural changes from fertilization to adulthood, includes embryology

Embryology

early developmental processes

Types of Microscopic Anatomy

Cytology- structure of cells

Histology- structure of tissues

Types of Physiology

Cell- cells and chemical processes

Organ-specific organs

Systemic- organ systems

Pathological- effects of diseases on organs/systems

Signs

objective disease indications (such as fever, measurable)

Symptoms

subjective disease indication (such as tiredness)

Six Levels of Organization

Chemical → Cellular → Tissue → Organ → Organ System → Organism

11 Body Systems

Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary, Male Reproductive, Female Reproductive

Integumentary System

Contains hair, skin, nails, sweat glands 

Functions: protective, regulates body temp, sensory info

Skeletal System

Contains bones, cartilage, associated ligaments, bone marrow

Function: structure, support and storage

Muscular System

Contains skeletal muscles and associated tendons

Function: movement, protection for tissues, generates heat

Nervous System

Contains brain, spinal cord, peripheral nerves, sense organs

Function: quick immediate responses, provides and interprets sensory info and external conditions

Endocrine System

Contains pituitary gland, thyroid gland, pancreas, adrenal glands, gonads, endocrine tissues in other systems

Function: directs long term changes, adjust metabolic activity and energy use by body, controls many structural and functional changes during development

Cardiovascular System

Contains Heart, blood, blood vessels, distribute blood, cells, water, and dissolved materials

Function: distribute heat and assist in control of body temperature 

Lymphatic System

Contains spleen, thymus, lymphatic muscles, lymph nodes, tonsils

Function: defends against infection and disease, returns tissue fluids to the bloodstream

Respiratory System

Contains nasal cavities, sinuses, larynx, trachea, bronchi, lungs, alveoli

Function: delivers air to alveoli (sites in lungs where gas exchange occurs), sends oxygen to blood stream, remove CO₂ from bloodstream, produce sounds for communication

Digestive System

Contains teeth, tongue, pharynx, esophagus, stomach, liver, gallbladder, pancreas, small and large intestine

Function: processes and digests food, absorbs and conserves water, nutrients, and stores energy

Urinary System

Contains kidneys, ureters, urinary bladder, urethra

Function: excretes water products from the blood, control water balance by regulating volume of urine produced, stores urine prior to voluntary elimination

Male Reproductive System

Contains testes, epididymides, ductus deferentia, seminal vesicles, prostate, peepee, scrotum 

Function: produces six cells/sperm seminal fluids and hormones, sexual intercourse

Female Reproductive System

Contains ovaries, uterine tubes, uterus, virgina, labia, clitoris, mammary glands 

Function: produces six cells/oocytes and hormones, supports developing embryo, provides milk, sexual intercourse

Surface Anatomy

Locating structures on or near the body surface

Anatomical Landmarks

Terms that correspond to specific surface landmarks of body

Anatomical position

standard anatomical reference position with hands at sides, palms forward, feet together

Anterior view 

anatomical position from front

Posterior view

anatomical position from back

Supine

face up

Prone

body lying face down

Abdominopelvic Quadrants 

Right upper quadrant, left upper quadrant, right lower quadrant, left lower quadrant

Abdominopelvic Regions 

Right hypochondriac region, epigastric region, left hypochondriac region, right lumbar region, umbilical region, left lumbar region, right inguinal region, hypogastric (pubic) region, left inguinal region

Proximal

Towards point of attachment/trunk

Distal

Away from point of attachment/trunk

Medial

toward midline

Lateral

away from midline

Cranial/Cephalic

toward head

Posterior/Dorsal

back surface

Anterior/Ventral

front surface

Caudal

toward the tailbone

Superior

above midline

Inferior

below midline

Superficial

close to surface

Deep

toward body interior

Sectional Anatomy

Section: slice through a three dimensional object

Used to visualize internal organization

Important for interpreting medical scans

Sectional plane

A single view or slice along a two dimensional flat surface

Frontal (coronal) plane

A vertical plane that divides the body or organ into anterior and posterior portions 

A cut in this plane is a frontal section (coronal section)

Sagittal plane

A vertical plane that divides the body or organ into left and right portions

A cut in this plane is called a sagittal section

Midsagittal plane lies in the middle

Parasagittal plane is offset from the middle

Transverse (horizontal) plane

A horizontal plane that divides the body or organ into superior and inferior portions

A cut in this plane is called a transverse section (cross section)

Body cavities

closed, fluid filled cavities that are lined by a thin serous membrane; contain the vital organs (viscera) of the trunk

Functions of Body Cavities

Protect delicate organs from shocks and impacts

Permit significant changes in the size and shape of internal organs

Serous Membrane (Serosa)

Lines body cavities and covers organs

Consists of parietal and visceral layers

Parietal serosa lines cavity 

Visceral serosa covers organs

Serous fluid moistens membranes and reduces friction 

Thoracic Cavity

Deep to the chest wall of the thoracic region

Divided by from the abdominopelvic cavity by the diaphragm

The thoracic cavity contains:

• Right and left pleural cavities which surround the lungs

• Pericardial cavity which surrounds the heart

• Mediastinum - a mass of connective tissue that stabilizes the trachea, esophagus, thymus, and largest vessels of the heart; also contains the pericardial cavity

Abdominopelvic Cavity

Deep to the abdominal and pelvic walls

Extends from the diaphragm to the pelvis

The abdomino pelvic cavity contains: 

• Superior abdominal cavity

• Inferior pelvic cavity

• Peritoneal cavity - space within the abdominopelvic cavity lined with peritoneum 

  • Parietal peritoneum lines the internal body wall

  • Visceral Peritoneum covers the organs

Abdominal Cavity

Extends from the diaphragm to the top of the pelvic bones

Contains digestive organs

Most abdominal organs are enclosed by the peritoneal cavity

Retroperitoneal space

Area of parietal peritoneum and  the back of the muscular body wall

Contains organs such as pancreas and kidneys

Pelvic Cavity

Medial to the pelvic bones

Contains the reproductive organs, rectum, and urinary bladder

Contains the inferior portion of the peritoneal cavity

Infraperitoneal

Organs which extend inferior to the peritoneal cavity, such as the urinary bladder, distal portion of the ureters, and large intestine

Homeostasis

The continuous physiological processes that establish a relatively stable internal environment

Physiological processes and systems respond to external and internal changes to keep variables within normal ranges (body temp, blood pressure, etc)

Homeostatic Regulation

The adjustment of physiological systems to preserve homeostasis

Autoregulation

mechanism of homeostatic regulation; automatic, local response to an environmental change in a cell, tissue, or organ

Extrinsic regulation

mechanism of homeostatic regulation; responses of organ systems controlled by the nervous system (through electrical signals) or the endocrine system (through chemical messengers)

• Nervous system directs rapid, short-term, responses

• Endocrine system directs slower, more long-term responses

A homeostatic regulatory mechanism consists of

Receptor: A sensor that detects the stimulus or change

Control center: Receives and processes the information and send out commands

Effector: A cell or organ that carries out the commands of the control center

- This helps limit fluctuations of internal conditions to keep them close to a set point, or desired value.

Negative Feedback

Returns it back to normal/ fights change

Helps maintain variables within a normal range

• Every loop is negative besides blood clotting, milk ejaculation, childbirth

Positive Feedback

Encourages change

The initial stimulus produces a response that amplifies the original change in conditions

Positive feedback loops

used when a potential dangerous process must be completed quickly to restore homeostasis

• Ex: blood clotting, milk ejaculation, childbirth

Systems integration

systems work together to maintain homeostasis

Any adjustments made by one physiological system have direct and indirect effects on a variety of other systems

Dynamic equilibrium

normal ranges can change