BackAnatomy & Physiology: The Human Body and Chemistry Essentials – Study Guide
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Chapter 1: The Human Body – An Orientation
Definitions and Principles
Anatomy: The study of the structure of body parts and their relationships to one another.
Physiology: The study of the function of the body’s structural machinery.
Principle of Complementarity: The concept that function always reflects structure; what a structure can do depends on its specific form.
Levels of Structural Organization
Organismal level: The human body is organized into several levels, from chemical to cellular, tissue, organ, organ system, and organism.
Major Organ Systems of the Human Body
The human body consists of 11 major organ systems, each with specific components and functions.
Organ system | Major organs | Overall function(s) |
|---|---|---|
(Integumentary system) | (Skin, hair, nails; cutaneous receptors and glands) | (Forms the external body covering, protects deeper tissues from injury, synthesizes vitamin D) |
(Skeletal system) | (Bones, cartilages, joints, tendons, ligaments) | (Protects and supports body organs, provides a framework the muscles use to cause movement; blood cell formation; mineral storage) |
(Muscular system) | (Muscles attached to skeleton (skeletal muscles)) | (Locomotion, facial expression, manipulation of the environment, maintain posture, generate heat) |
(Nervous system) | (Brain, spinal cord, nerves) | (Fast-acting control system of the body; responds to internal and external changes by activating effectors) |
(Endocrine system) | (Pituitary, thyroid, adrenal, parathyroid, pineal glands; gonads, pancreas, thymus) | (Glands secrete hormones that regulate processes such as growth, reproduction, and metabolism) |
(Cardiovascular system) | (Heart and blood vessels) | (Heart pumps blood; blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc.) |
(Lymphatic system/Immunity) | (Lymphatic vessels, lymph nodes, spleen, thymus) | (Picks up fluid leaked from blood vessels, returns it to blood; disposes of debris and pathogens; houses WBCs involved in immunity) |
(Respiratory system) | (Nasal cavity, pharynx, larynx, trachea, bronchi, lungs) | (Keeps blood constantly supplied with oxygen and removes carbon dioxide) |
(Digestive system) | (Oral cavity, esophagus, stomach, small/large intestine, rectum, liver) | (Breaks food down into absorbable units that enter blood for distribution to body cells; removes indigestible wastes as feces) |
(Urinary system) | (Kidneys, ureters, urinary bladder, urethra) | (Eliminates nitrogenous wastes from the body; regulates water, electrolyte, and acid-base balance of blood) |
(Reproductive system (male/female)) | (Male: testes, prostate, ductus deferens, scrotum; Female: ovaries, uterine tubes, uterus, vagina, mammary glands) | (Testes produce sperm and testosterone; ovaries produce eggs and estrogen/progesterone; uterus develops fetus; mammary glands produce milk for the infant) |
Requirements for Life
Term | Definition |
|---|---|
Maintaining boundaries | The defined limits of a physical object that constrain distribution of substances to one side or the other (e.g., epithelial barriers separating body cavities). |
Movement | Motion of the entire body, or individual body parts, including organs, tissues, and cells. |
Responsiveness | The ability to sense changes (stimuli) in the environment and then respond to them. |
Digestion | The breaking down of ingested foodstuffs to building blocks that can be absorbed into the blood. |
Metabolism | All of the chemical reactions that occur within body cells. |
Excretion | The process of removing wastes from the body. |
Reproduction | (1) A process by which stimulated cells divide to create additional body mass (growth) or replace dead cells (maintenance/repair); for example, mitotic division to replace dead cells lining blood vessels to prevent blood loss. (2) A mechanism used to produce a new organism. |
Growth | An increase in the size of an organism or body part due to an increase in the number of cells or the size of individual cells. |
Homeostasis
Homeostasis is a dynamic state of equilibrium in which internal conditions vary within narrow limits.
Three main parts of a homeostatic control system:
Receptor: Responds to stimuli (changes) by sending information (input) along the afferent pathway to the control center.
Control center: Determines the set point at which a given variable is to be maintained. Processes incoming information from receptors and determines appropriate responses by communicating with effectors.
Effector: Carries out the control center’s response to the stimulus.
Negative and Positive Feedback Mechanisms
Example | Negative or positive feedback mechanism? |
|---|---|
Blood clotting | (Positive) |
Body temperature | (Negative) |
Labor contractions | (Positive) |
Blood sugar levels | (Negative) |
Blood pressure | (Negative) |
Homeostatic imbalance can lead to disease. The efficiency of negative feedback mechanisms declines with age, increasing risk of illness.
Additional info: For example, older adults have a higher risk of dehydration because total body water often decreases (muscle declines and body fat increases); they may become less responsive to thirst cues.
Anatomical Terms: Body Directions, Regions, and Planes
Directional Term | Definition | Example |
|---|---|---|
Superior (cranial) | Toward the head end or upper part of a structure or the body; above | Thoracic cavity is superior to the abdominal cavity |
Inferior (caudal) | Away from the head end or toward the lower part of a structure or the body; below | Forehead is superior to the nose |
Anterior (ventral) | Toward or at the front of the body; in front of | Thoracic cavity is anterior to the vertebral cavity |
Posterior (dorsal) | Toward or at the back of the body; behind | The spine is posterior to the heart |
Medial | Toward or at the midline of the body; on the inner side of | The nose is medial to the ears |
Lateral | Away from the midline of the body; on the outer side of | The shoulder is lateral to the neck |
Intermediate | Between a more medial and a more lateral structure | The ring finger is intermediate between the thumb and the little finger |
Proximal | Closer to the origin of the body part or the point of attachment of a limb to the body trunk | The knee is proximal to the toes |
Distal | Farther from the origin of a body part or the point of attachment of a limb to the body trunk | The wrist is distal to the elbow |
Superficial (external) | Toward or at the body surface | The skin is superficial to the bones |
Deep (internal) | Away from the body surface; more internal | The skeletal muscles are deep to the skin |
Serous Membranes
Allow visceral organs to slide without friction across the cavity walls and one another.
In ventral body cavities, organs are covered by serous membranes called serosa.
Organs in the dorsal body cavities (brain and spinal cord) do not require lubricating serous fluid because they do not move.
Chapter 2: Chemistry Comes Alive
Energy: Potential vs. Kinetic
Kinetic or potential energy | Example |
|---|---|
(Potential energy) | Food molecules in the stomach |
(Kinetic energy) | The passage of food to the stomach |
(Kinetic energy) | The release of a stretched rubber band |
(Potential energy) | A stretched rubber band |
(Kinetic energy) | Water flowing down a river |
Elements, Molecules, and Compounds
Chemical element: A unique variety of matter that cannot be broken down into simpler substances by ordinary chemical means. Examples: carbon, oxygen, hydrogen, nitrogen.
Molecule: A combination of two or more atoms held together by chemical bonds.
Compound: A substance composed of two or more different elements, the atoms of which are chemically united.
Chemical Bonds
Chemical bond type | Description or example |
|---|---|
(Hydrogen) | Attraction between a hydrogen atom carrying a partial positive charge and an electronegative atom with a slightly negative charge |
(Covalent) | Bond within a water molecule |
(Covalent) | Sharing of pairs of electrons |
(Ionic) | Intermediate strength of the three types of bonds |
(Covalent) | Strongest strength of the three types of bonds |
(Ionic) | Attraction between two oppositely charged ions |
(Hydrogen) | Bonds between adjacent water molecules |
(Hydrogen) | Weakest strength of the three types of bonds |
(Ionic) | Sodium chloride (table salt) |
Polar covalent bonds: Electrons are shared unequally.
Nonpolar covalent bonds: Electrons are shared equally.
Chemical Reactions
Reversible reaction: A reaction in which the forward reaction (to the right) and the reverse reaction (to the left) both occur. The dominant direction is indicated by the longer arrow.
Irreversible reaction: A reaction in which the forward reaction predominates over the reverse reaction.
Water and Salts in Body Homeostasis
Water is a polar molecule, allowing ionic compounds like NaCl (salt) to dissociate in water.
High heat capacity: Water absorbs and releases large amounts of heat before changing temperature.
High heat of vaporization: Water requires large amounts of heat to evaporate, providing cooling (e.g., sweating).
Electrolytes: Chemical substances (salts, acids, bases) that ionize and dissociate in water and are capable of conducting an electrical current.
Important Ions in the Body
Ionic sodium (Na+): Important for water balance, conduction of nerve impulses, and muscle contraction.
Ionic potassium (K+): Necessary for conduction of nerve impulses and muscle contraction (major positive ion in cells).
Ionic calcium (Ca2+): Required for muscle contraction, conduction of nerve impulses, and blood clotting.
Enzymes
Enzymes: Biological catalysts that increase the rate of chemical reactions without themselves being chemically changed or part of the products.
Summary Table: Kinetic vs. Potential Energy
Type of Energy | Example |
|---|---|
Kinetic | Water flowing down a river |
Potential | Food molecules in the stomach |
Additional info: These notes cover foundational concepts in anatomy and physiology, including body organization, requirements for life, homeostasis, anatomical terminology, and basic chemistry relevant to biological systems.
