Introduction to Human Anatomy and Physiology - Week 2

A set of study prompts (questions) with concise answers covering key concepts from Week 2, including fundamentals of anatomy and physiology, levels of organization, structural terminology, organ systems, homeostasis, planes, positional terms, body cavities, and common imaging and clinical positions.

Relationship between Anatomy and Physiology

Anatomy studies the structure of the body; Physiology studies how those structures function. Together, they explain how body parts are built to perform their roles.

Anatomy

Study of structures

Cell physiology

Study of the functions of living cells

Special physiology

The study of functions of specific organs

Pathologic physiology

The study of the effects of diseases on organs

Physiology

Study of functions of different human structures

List the levels of organization of the human body from simplest to most complex.

Chemicals → Atoms → Molecules → Macromolecules → Cells → Tissues → Organs → Organ systems.

Six functional characteristics of human life

Organization, Metabolism, Responsiveness, Movement, Development, Reproduction.

Anatomical Position

Standing upright with feet shoulder-width apart, toes forward; upper limbs at sides; palms facing forward

Supine position

Laying face forward

Prone position

Laying facing down

Gross (Macroscopic) Anatomy

The study of larger body structures visible without magnification.

Regional Anatomy

Study of interrelationships of structures in a specific region (e.g., muscles, nerves, vessels in a region).

Systemic Anatomy

Study of the structures that make up a discrete body system that performs a specific function.

Study of specific Organ system

Surface Anatomy

Study of landmarks on the body's surface to locate visceral organs.

Study of visible external organs without the need for dissection

Embryology

Study of development of the human body from fertilization to extrauterine life.

Neuroanatomy

Study of the nervous system’s normal microscopic and gross features and development.

Microscopic Anatomy

Study of structures observable only with a microscope.

Cytology

Study of cells at the cellular level (structure and function).

Histology

Study of the normal tissues of the body.

Homeostasis

The state of steady internal conditions maintained by living things, involving regulation of factors like temperature, fluids, and hormones.

Components of control systems in homeostasis

Receptors (sensors), a set point, and effectors (muscles or glands) that respond to restore balance.

Receptors

Monitor for changes

Set point

Normal value or range of values

Effectors

Muscles or glands that respond to the changes to return to stability

Negative Feedback

A response that reduces or shuts off the original stimulus, restoring homeostasis.

To lower the increase.. e.g. High blood pressure or fever

Positive Feedback?

A response that amplifies a change, moving away from the set point; it’s normal only when there is an endpoint (e.g., childbirth).

To intensify a change in the body… e.g. hypothermia, low blood pressure

Kinds of Body planes

Sagittal (including midsagittal/median and parasagittal), Frontal (coronal), and Transverse planes.

Body planes

Imaginary two-dimensional surface that passes through the body

Sagittal plane

Plane that divides the body vertically into left and right side

Midsagittal (median) plane

A vertical plane that divides the body into equal left and right halves.

Frontal (coronal) plane

A vertical plane that divides the body into anterior (front) and posterior (rear) portions.

Transverse plane

A horizontal plane that divides the body into superior (upper) and inferior (lower) portions.

Superior

toward the head or upper part

Inferior

means toward the feet or lower part

Anterior (ventral)

Toward the front of the body

Posterior (dorsal)

toward the back

Medial

toward the midline

Lateral

toward the side

Distal

Away from the point of attachment or origin

Proximal

nearer to the point of attachment

Superficial

closer to the body surface

Deep

farther from the surface

Body cavities membranes

Posterior (dorsal) cavity: cranial and spinal cavities. Anterior (ventral) cavity subdivides into thoracic and abdominopelvic

Serous membrane

thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities

Parietal layers

It line the walls of the body cavity (pariet- cavity wall)

Visceral layer

It covers the organs (viscera)

Pleura

The serous membrane that surrounds the lungs in the pleural cavity

Pericardium

A serous membrane that surrounds the heart in pericardial cavity

Peritoneum

The serous membrane that surrounds several organs in the abdominopelvic cavity

serous membranes and their cavities

Pleura (lungs) in the pleural cavity; Pericardium (heart) in the pericardial cavity; Peritoneum (abdominopelvic organs) in the peritoneal cavity.

X-ray

Visualizes hard structures like teeth and bones; exposure involves ionizing radiation, so shielding and limiting exposure are important.

Computed Tomography (CT)

Noninvasive cross-sectional X-ray imaging that creates two-dimensional slices via rotating scans and computer reconstruction.

Magnetic Resonance Imaging (MRI)

Noninvasive imaging using magnetic fields and radio waves without ionizing radiation; drawbacks include cost, noise, patient comfort, and MRI contraindications with certain implants.

Positron Emission Tomography (PET)

Imaging that shows physiologic activity (metabolism, blood flow) using radiopharmaceuticals; helpful in heart disease, cancer spread, infections, brain and bone diseases.

Ultrasonography (Ultrasound)

Uses high-frequency sound waves to create real-time images; least invasive; operator-dependent and limited by bone and gas interference.

Fowler’s position

Sitting with the trunk elevated about 30–45 degrees.

Trendelenburg position

Supine with the head lower than the feet to improve certain surgical access or venous return.

Reverse Trendelenburg position

Head elevated above the feet to reduce blood loss and improve access in some abdominal and neck procedures.

Lithotomy position

A supine position with hips and knees flexed and legs supported in elevation (common in gynecologic and urologic procedures).

RUQ, LUQ, RLQ, and LLQ

Quadrants of the abdomen used to describe the location of organs or pain.

Main role of the Integumentary system in homeostasis

Protection and thermoregulation (skin, hair, nails) helping regulate internal conditions.

Major function of the Cardiovascular system in homeostasis regulation

Circulation maintains blood pressure and distributes nutrients, gases, and wastes.

Major function of the Lymphatic system in homeostasis

Defense against pathogens and return of fluid to the blood.

Major function of the Nervous system in homeostasis

Rapid regulation and coordination of body activities through nerve signals.

Major function of the Digestive system in homeostasis

Absorption, storage, and processing of nutrients for energy and growth.

Major function of the Urinary system in homeostasis

Regulation of blood volume and composition; excretion of wastes.

Major function of the Endocrine system in homeostasis

Secretion of regulatory hormones that influence metabolism, growth, and homeostasis.

organs in the right hypochondriac

Liver, gallbladder, right kidney, small intestine

organs in the epigastric region

Stomach, liver, pancreas, duodenum, spleen, and adrenal glands

organs in the left hypochondriac region

Spleen, colon, left kidney, pancreas

organs in the right lumbar region

Gallbladder , liver, right colon

organs in the umbilical region

Navel, parts of intestine, and duodenum

organs in the left lumbar

Descending colon and left kidney

organs in the right iliac

Appendix and cecum

organs in the Hypogastric region

Urinary bladder, sigmoid colon, and female reproductive organs

organs in the left iliac

Descending colon and sigmoid colon