The science of body structures and the relationships among structures
The science of body functions
Chemical level of organization
Includes atoms and molecules.
Cellular level of organization
The basic structural and functional living units of an organism and the smallest living units in the human body.
Tissue level of organization
Groups of cells and the materials surrounding them that work together to perform a particular function
Organ level of organization
Composed of two or more different types of tissues; they have specific functions and usually have recognizable shapes
System level of organization
Composed of two or more related organs that have a common function
Organism level of organization
Any living individual.
The levels of organization
Chemical -> Cellular -> Tissue -> Organ -> System -> Organism
The condition of equilibrium in the body's internal environment due to the ceaseless interplay of the body's many regulatory systems.
The components of a feedback system
Receptor, control centre and effector
Negative vs. Positive Feedback Systems
Negative feedback systems reverse a change in a controlled condition. Positive feedback systems strengthen or reinforce a change in one of the body's controlled conditions.
The anatomical position
The subject stands erect facing the observer, with head level and eyes facing directly forward. Feet are flat on floor and directed forward. Arms are at the sides with palms turned forward.
Smallest unit of matter that participate in chemical reactions
Two or more atoms joined together
Basic life processes (6)
Metabolism, Responsiveness, Movement, Growth, Differentiation and Reproduction
Intracellular fluid (ICF)
Fluid within cells.
Extracellular fluid (ECF)
Fluid outside of cells.
Extracellular fluid that fills the narrow spaces between cells of tissues.
A body structure that monitors changes in a controlled condition and sends input to a control center.
Sets the range of values within which a controlled condition should be maintained (i.e. the brain)
External, internal or environmental imbalances in homeostasis. Usually mild and temporary.
The body is lying face down.
The body is lying face up.
The sum of all chemical processes that occur in the body.
The body's ability to detects and respond to changes.
Includes motion of the whole body, individual organs, single cells and tiny structures within cells.
An increase in body size that results from an increase in the size of existing cells, the number of cells or both. In addition, a tissue sometimes increases in size because the amount of material between cells increases.
The development of a cell from an unspecialized to a specialized state
A reference to either the formation of new cells for tissue growth, repair or replacement, or the production of a new individual.
Receives output from the control centre and produces a response or effect that changes the controlled condition. Nearly every organ or tissues can behave as one.
Feedback system example
When body temperature drops sharply, the brain (control centre) sends nerve impulses (output) to skeletal muscles (effectors).
The breakdown of complex substances into simpler components
The building up of complex chemical substances from smaller, simpler components.
A cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored and reevaluated.
Positive feedback system
A reinforcement or strengthening of a change in one of the body's controlled conditions. Because a positive feedback system does this, some event outside the system must shut it off.
Any abnormality of structure or function
Specific term for an illness characterized by a recognizable set of signs and symptoms.
Subjective changes in body function that are not apparent to any observer
Objective changes in body structure or function that a clinician can observe and measure.
Top of foot
Digital or Phalangeal
Anterior surface of knee
Front of elbow
Area from the chest down to the pelvis
Area below the ribs and above the pelvis
Base of skull
Back of elbow
Hollow behind knee
Back of hand
Loin (lower back)
Imaginary flat surfaces that pass through the body parts
A vertical plane that divides the body or an organ into right and left sides
A sagittal plane that passes through the midline of the body or an organ and divides it into equal right and left sides
A sagittal plane that divides the body or an organ into unequal right and left sides
Divides the body or an organ into anterior and posterior portions
Divides the body into superior (upper) and inferior (lower) portions. Also known as cross-sectional or horizontal plane.
Passes through the body or an organ at an angle between the transverse plane and either a sagittal or frontal plane
One flat surface of a 3D structure or a cut along a plane.
Three different Sections
Transverse section, Frontal section, Midsagittal section
Spaces within the body that help protect, separate and support internal organs.
What separates various body cavities from one another?
Bones, muscles, ligaments and other structures
Contains the brain. Formed by the cranial bones.
Vertebral (spinal) cavity
Contains the spinal cord. Formed by the bones of the vertebral column.
Three layers of protective tissues that lines the cranial cavity and the vertebral cavity.
2 major body cavities of the trunk
Thoracic and Abdominopelvic cavities
Thoracic (chest) cavity - what is it formed by?
Formed by the ribs, the muscles of the chest, the sternum (breastbone) and the thoracic portion of the vertebral column.
Thoracic cavity - contains 4 other cavities
Pericardial cavity: fluid-filled space that surrounds the heart
2 pleural cavities: each one surrounds a lung and contains a small amount of fluid.
Mediastinum: central part of the thoracic cavity. Between the lungs, extending from sternum to vertebral column and from neck to diaphragm. Contains heart, thymus, esophagus, trachea and several large blood vessels.
A dome-shaped muscle that separates the thoracic cavity from the abdominopelvic cavity.
Abdominopelvic cavity - general
Extends from the diaphragm to the groin and is encircled by the abdominal wall and the bones and muscles of the pelvis. Divides into two portions, although no wall separates them.
Abdominopelvic cavity - specific
Abdominal cavity (superior portion) - contains the stomach, spleen, liver, gallbladder, small intestine and most of the large intestine.
Pelvic cavity (inferior portion) - contains the urinary bladder, portions of the large intestine and internal organs of the reproductive system.
Organs inside the thoracic and abdominopelvic cavities.
Membranes of the thoracic and abdominal cavities
Thin, slippery, double layerd serous membrane which covers the viscera and lines the walls of the thorax and abdomen.
Parts of the serous membrane
1) the parietal layer - lines the walls of the cavities
2) visceral layer - covers and adheres to the viscera within the cavities
Reduces friction between the parietal and visceral layers, allowing the viscera to slide somewhat during movements (i.e. when lungs inflate and deflate during breathing)
3 Different types of serous membranes
Pleura, pericardium and peritoneum
The serous membrane of the pleural cavities.
The serous membrane of the pericardial cavity.
The serous membrane of the abdominal cavity
Contains the teeth and tongue.
Within the nose.
Contain the eyeballs.
Middle ear cavities
Contain small bones in the middle ear
Found in the freely movable joints and contain synovial fluid
What do disruptions of homeostasis lead to?
Disorders, diseases and death.
What is the origin of disruptions of homeostasis?
External and internal stimuli and psychological stresses
Which systems regulate homeostasis and how?
The nervous and endocrine systems.
The nervous system detects body changes and sends nerve impulses to counteract changes in controlled conditions. The endocrine system regulates homeostasis by secreting hormones.
Name the 3 components of a feedback system
Receptors, Control Centre and Effectors
Describe the 3 components of a feedback system
1) Receptors monitor changes in a controlled condition and send input to a control centre
2) The control centre sets the value at which a controlled condition should be maintained, evaluates the input it receives from receptors and generates output commands when they are needed.
3) Effectors receive output from the control center and produce a response (effect) that alters the controlled condition.
Difference between negative and positive feedback systems
If a response reverses the original stimulus, the system is operating by negative feedback. If a response enhances the original stimulus, the system is operating by positive feedback.
Example of negative feedback
The regulation of blood pressure. If a stimulus causes blood pressure (controlled condition) to rise, baroreceptors in blood vessels send impulses (input) to the brain (control centre), which sends impulses (output) to the heart (effector). As a result, heart rate decreases (response) and blood pressure decreases to normal (restoration of homeostasis).
Example of positive feedback
Labour. When it begins, the cervix of the uterus is stretched (stimulus) and stretch-sensitive nerve cells in the cervix (receptors) send nerve impulses (input) to the brain (control centre). The brain responds by releasing oxytocin (output), which stimulates the uterus (effector) to control more forcefully (response). Movement of the fetus further stretches the cervix, more oxytocin is released and even more forceful contractions occur. The cycle is broken with the birth of the baby.
4 basic types of tissue in the body
epithelial, connective, muscular and nervous
Homeostatic imbalance leads to...
disorder (any abnormality of structure/function) and disease (specific term for an illness characterized by a recognizable set of signs/symptoms)
extracellular fluid within blood vessels
The way the body regulates its internal environment. A feedback system is a cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored etc.
Nerves and chemical signals