Defin These Terms Flashcards
Organ
A group of tissues specialized for a particular function
Tissue
Groups of cells forming various building materials of the body
Homeostasis
A state of dynamic equilibrium in the body with respect to its internal environment and functions.
Set point
Ideal normal value of a variable around which homeostasis is maintained through a normal range of values that are acceptable to the body
Stress
A factor that causes one or more physiological variables to move away from its homeostatic set point
Control center
The part of the body, either central nervous system or endocrine gland, that receives information about a variable, determines the set point, and signals a response to correct imbalances
Receptor
A structure in the body that monitors the values of your body’s variables
Effector
A structure in the body that can change the value of variable in response to a signal from the control center
Negative-Feedback System
A control mechanism consisting of receptors, control center, and effectors through which homeostasis in the body is maintained by regulation of the body’s organ systems. It is called negative feedback because the control system opposes or reverses the original stress.
Selective permeability
The ability to let certain materials in or out while restricting others
Endocytosis
The process by which large molecules are taken into the cell
Exocytosis
Transportation of material from inside the cell to outside the cell using vesicles: also called secretion
Exocrine glands
Glands that secrete substances outward through a duct
Endocrine glands
Ductless glands that secrete hormones into the bloodstream
Merocrine glands
Exocrine glands that secrete without losing cellular material
Apocrine glands
Exocrine glands that have cytoplasm in their secretions
Holocrine glands
Exocrine glands that have secretions made up of disintegrated cells
Extracellular matrix
The chemical substances located between connective tissue cells
Fibroblasts
Spindle-shaped cells that form connective tissue proper
Stromal cells
“ Supporting” cells that provide structure or support for parenchymal cells
Parenchymal cells
“Performance” cells that provide the actual function of the tissue
Labile cells
Cells that undergo mitosis regularly and quickly
Stable cells
Cells that do not regularly undergo mitosis but are able to if the need arises
Permanent cells
Cells that cannot undergo mitosis
Epidermis
The outer portion of the skin, formed by epithelial tissue that is attached to the dermis
Dermis
Dense irregular connective tissue that forms the deep layer of skin
Hypodermis
Loose connective tissue underneath the dermis that connects the dermis to muscle or bone
Hemopoiesis
The process of manufacturing blood cells
Histology
The study of tissues
Compact bone
Dense bone matrix organized into microscopic tubes of bone called osteons
Cancellous bone
Network of bone with many marrow-filled spaces surrounding the bone matrix
Ossification
Bone formation
Articular cartilage
Hyaline cartilage that covers the ends of a bone in a joint
Axial skeleton
The portion of the skeleton that supports and protects the head, neck,and trunk
Appendicular skeleton
The proration of the skeleton that attaches to the axial skeleton and has the limbs attached to it
Suture
An immovable joint between flat bones of the skull
Process
A projection on a bone
Meatus
A passageway
Foramen
A hole
Sinus
A hollowed out space in a bone
Osteoblast
A bone forming cell
Osteocyte
A mature bone cell surrounded by bone matrix
Osteoclast
A large, multinucleated cell that breaks down bone
Hematoma
A mass of blood that is confined to a limited space
Callus
A mass of connective tissue that connects the ends of a broken bone
Anatomical position
The position acquired when one stands erect with the feet facing forward , the upper limbs hanging at the sides, and the palms facing forward with the thumbs to the outside
Sarcomere
The repeating unit of a myofibril
Neuron
The functional unit of the nervous systems, a nerve cell
Synapse
The interface between a neuron and another cell
Neurotransmitter
A chemical released by neuron, which diffuses across the synaptic cleft, enabling the neuron to communicate with another cell.
Motor unit
One motor neuron and all the muscle fibers it innervates
All-or-none law of skeletal muscle contraction
An individual muscle fiber contracts maximally in response to an action potential
Subthreshold stimulus
A stimulus to small to create an action potential in a neuron
Threshold stimulus
A stimulus strong enough to create one action potential in a neuron
Submaximal stimuli
Stimuli of increasing strength that create more action potentials along more neurons
Maximal stimulus
A stimulus that is strong enough to create action potentials on all motor neurons to a particular muscle
Muscle tone
The state of partial contraction in a muscle, even when the muscle is not being used.
Origin
The point at which a muscle’s tendon attaches to the more stationary
Insertion
The point at which a muscle’s tendon attaches to the more moveable bone
Belly
The largest part
Mastication
The process of chewing
Extrinsic hand muscles
Muscles in the forearm that create movement in the hands.
Intrinsic hand muscle
Muscles in the hand that produce movement in the hand.
Nerves
Bundles of neuron axons and their coverings, which are found outside the CNS
Ganglia
Collection of neuron cell bodies that are found outside the CNS
Spinal nerves
Nerves that originate from the spinal cord
Cranial Nerves
Nerves that originate from the brain.
Afferent neurons
Neurons that transmit action potentials from the sensory organs to the CNS.
Efferent Neurons
Neurons that transmit action potentials from CNS to the effector organs.
Somatic motor nervous system
PNS neurons that transmit action potentials from the CNS to skeletal muscle
Autonomic nervous system
PNS neurons that transmit action potentials from CNS to smooth muscles, cardiac muscles, and glands
Sympathetic division
Division of the ANS that generally prepares the body for increased energy expenditure.
Parasympathetic division
Division of the ANS that regulates resting and nutrition-related functions such as digestion, defecation, urination
Association neuron
A neuron that conducts action potentials from one neuron to another neuron within the CNS.
Excitability
The ability to undergo an action potential in response to a stimulus
Potential difference
A measure of the charge difference across the cell membrane.
Gray Matter
Collections of neurons cell bodies and their associated neuroglia
White Matter
Bundles of parallel axons and their coverings.
Decussation
The anatomical crossing over of neurons from left to right.
Vital functions
Those functions of the body necessary for life
Commissures
Connections of neurons axons that allow the two hemispheres of the brain to communicate with one another
Sensory receptors
An organ that responds to a specific type of stimulus by triggering an action potential on sensory neuron
Somatic receptors
Sensory receptors in the skin, muscle, and tendons
Visceral receptors
Sensory receptors in the internal organs
Special receptors
Sensory receptors in specific locations
Mechanoreceptors
Sensory receptors that respond to movement, weather it is light touch, vibration, or pressure.
Thermoreceptors
Sensory receptors that respond to heat or cold.
Photoreceptors
Sensory receptors that respond to light
Chemoreceptors
Sensory receptors that respond to chemicals
Nociceptors
Sensory receptors that respond to several types of excess stimulation, which is termed pain
Cutaneous receptors
Receptors in the skin
Proprioceptors
Receptors in the skeletal muscle and tendons
Static equilibrium
Determines the orientation of the head relative to the pull of gravity. In other words, it helps the body determine whether the head is being held up straight, bowed, leaned to one side, and so forth.
Dynamic equilibrium
helps determine the rotation and acceleration of the head. This allows us to maintain balance as we move.
Neurosecretory cells
Neurons of the hypothalamus that secrete neurohormones rather than neurotransmitters.
Prostaglandins
Biologically active lipids that produce many effects in the body, including smooth muscle contraction, which inflammation, and blood clotting.
Viscosity
The resistance to flow and alteration of shape due to cohesion
Plasma
The fluid portion of the blood, which is mostly water, about 55% by volume
Formed elements of the blood
The red blood cells, white blood cells, and fragments called platelets, about 45% by volume
Erythrocytes
Red blood cells that carry the oxygen in blood.
Leukocytes
White blood cells that preform defensive functions in blood
Thrombocytes
Cell fragments in blood that help prevent blood loss
Diapedesis
Passage of white blood cells through pores in blood vessel to get into the tissue spaces
Chemotaxis
Attraction of cells to chemical stimuli
Phagocytosis
Literally, cell-eating. The process by which a cell engulfs and ingests a foreign or dead cell or cell part.
Pus
A mixture of dead or dying white blood cells foreign cells such as bacteria, and fluid.
Hemopoiesis
The process by which the formed elements of blood are made in the body
Hemostasis
The process by which the body stops blood loss
Coagulation factors
Proteins in blood plasma that help initiate the blood coagulation process
Antigen
A protein or other molecule that, when introduced into the body, triggers the production of an antibody.
Arteries
Blood vessels that carry blood away from the heart
Capillaries
Microscopic, thin-walled blood vessels that allow the exchange of gases and nutrients between the blood and body cells
Veins
Blood vessels that carry blood back to the heart.
Pulmonary circulation
Circulation of the blood around the alveoli (air sacs) of the lungs.
Systemic circulation
Circulation of the blood through the other tissues of the body.
Diastole phase
The phase of the cardiac cycle in which the ventricles contract
Cardiac cycle
One complete round of diastole and systole.
Arterioles
The smallest arteries that still have three tunics.
Venules
Small veins that do not have three tunics, but instead have only an endothelium, a basement membrane, and a few smooth muscle cells.
Lymphatic tissue
Groups of lymphocytes and macrophages that provide immune protection
Lymph nodes
Encapsulated masses of lymphatic tissue found along lymph vessels.
Lymph
Watery liquid formed from interstitial fluid and found in lymph vessels
Edema
A buildup of excess interstitial fluid in the tissues, which leads to swelling.
Immunological defense
The process by which the body protects itself from pathogenic invaders such as bacteria, fungi,parasites, and foreign substances.
Mucosa-associated lymphoid tissue (MALT)
Concentration of lymphatic tissue without a connective tissue capsule
Diffuse lymphatic tissue
Scattered lymphatic, macrophages, and other cells found deep to mucous membranes
Lymph nodules
Lymphatic tissue arranged into compact, somewhat spherical structures, but without a capsule
Innate immunity
An immune response response that is the same regardless of the pathogen or toxin encountered
Acquired immunity ( also called specific or adaptive immunity )
An immune response targeted at a specific pathogen or toxin after exposure.
Complement
A series about 30 plasma proteins activated by foreign cells or antibodies to those cells. They lyse bacteria, promote phagocytosis, and promote inflammation.
Interferon
Proteins secreted by cells infected with a virus. These proteins do not save the infected cell, but simulate nearby cells to strengthen themselves against a viral invasion.
Pyrogens
Chemicals that promote fever by acting on the hypothalamus.
Humoral immunity
Acquired immunity provided by antibodies in the blood plasma
Cell-mediated immunity
Acquired immunity provided by T lymphocytes
