Bio Ch 31 Flashcards
Tissue
composed of specialized cells of the same or similar type that perform a common function in the body
Epithelial tissue (epithelium)
consists of tightly packed cells that form a continuous layer; covers surfaces and lines body cavities
Basement membrane
thin layer of various types of proteins that anchors the epithelium to the extracellular matrix (often a type of connective tissue)
Squamous epithelium
composed of flattened cells; found lining blood vessels and the air sacs of lungs
Cuboidal epithelium
cube-shaped cells and is found lining the kidney tubules and various glands
Columnar epithelium
has cells resembling rectangular pillars or columns, with nuclei usually located near the bottom of each cell; found lining the digestive tract, where it efficiently absorbs nutrients from the small intestine because of minute cellular extensions called microvilli
Gland
can be a single epithelial cell, as in the case of mucus-secreting goblet cells within the columnar epithelium lining the digestive tract, or a gland may contain many cells
Exocrine glands
glands that secrete their products into ducts
Endocrine glands
glands that have no duct (pituitary, thyroid); secrete hormones internally, so they are transported by the bloodstream
Connective tissue
the most abundant and widely distributed tissue in complex animals; diverse in structure and function; 3 components - specialized cells, ground substance, protein fibers
Collagen fibers
white fiber in the matrix of connective tissue giving flexibility and strength
Reticular fibers
very thin collagen fibers that are highly branched and form delicate supporting networks
Elastic fibers
yellow fiber containing elastin, a protein that is not as strong as collagen but is more elastic
Fibroblasts
both loose fibrous and dense fibrous connective tissues have cells called this that are located some distance from one another and are separated by a jellylike matrix containing white collagen fibers and yellow elastic fibers
Loose fibrous connective tissue
supports epithelium and also many internal organs; its presence in lungs, arteries, and the bladder allows these organs to expand
Adipose tissue
serves as the body’s primary energy reservoir
Dense fibrous connective tissue
contains many collagen fibers that are packed together; has more specific functions than does loose connective tissue
Tendons
connect muscles to bones
Ligaments
connect bones to other bones at joints
Cartilage
cells lie in small chambers called lacunae (sing. lacuna), separated by a matrix that is solid yet flexible
Lacuna (pl. lacunae)
small pit or hollow cavity, as in bone or cartilage, where a cell or cells are located
Hyaline cartilage
most common type of cartilage; contains only very fine collagen fibers; found in nose, ends of long bones and ribs; forms rings in the walls of respiratory passages; fetal skeleton also made of this type of cartilage
Elastic cartilage
has more elastic fibers than hyaline cartilage; more flexible; found in the framework of the outer ear
Fibrocartilage
has a matrix containing strong collagen fibers; found in structures that withstand tension and pressure, such as the pads between the vertebrae in the backbone and the wedges in the knee joint
Bone
of all connective tissues, this is the most rigid; consists of an extremely hard matrix of inorganic salts, notably calcium salts, deposited around protein fibers, especially collagen fibers
Compact bone
makes up the shaft of a long bone; consists of cylindrical structural units called osteons (Haversian systems)
Spongy bone
contains numerous bony bars and plates, separated by irregular spaces; lighter than compact bone; designed for strength; site of red bone marrow
Blood
consists of formed elements and plasma; fluid connective tissue located in blood vessels
Tissue fluid
internal environment of the body consists of blood and this; blood creates this; blood transports nutrients and oxygen to this and removes carbon dioxide and other wastes
Red blood cells
small, disk-shaped cells without nuclei; makes the cell biconcave; contains hemoglobin
White blood cells
large, have a nucleus; transparent; nucleus typically looks blue or purple; fight infection
Pathogens
some white blood cells are phagocytic and engulf infectious these
Platelets
not complete cells; fragments of large cells present only in bone marrow; when a blood vessel is damaged, these form a plug that seals the vessel, and injured tissues release molecules that help the clotting process
Lymph
fluid connective tissue located in lymphatic vessels; absorb excess tissue fluid and return it to the cardiovascular system
Lacteals
special lymphatic capillaries which absorb fat molecules from the small intestine
Muscular (contractile tissue)
composed of cells called muscle fibers, which contain actin and myosin filaments, whose interaction accounts for movement and are also important in the generation of body heat
Skeletal muscle
voluntary muscle; attached by tendons to the bones of the skeleton; when it contracts, body parts move; cylindrical, long
Striated
having bands; in cardiac and skeletal muscle, alternating light and dark bands produced by the distribution of contractile proteins
Smooth (visceral) muscle
cells lacking striations; spindle-shaped; involuntary
Cardiac muscle
found only in the walls of the heart; contraction pumps blood and accounts for the heartbeat
Nervous tissue
contains nerve cells called neurons and supporting cells called neuroglia
Neuron
specialized cell with 3 parts - dendrites, a cell body, and an axon
Nerves
fibers bound by connective tissue form these outside the brain and spinal cord
Neuroglia
nervous tissue contains these cells in addition to neurons; outnumber neurons 10 to 1; make up approximately half the volume of the organ; primary function to support and nourish neurons; some directly contribute to brain function
Organs
composed of 2 or more types of tissues working together to perform a particular function
Organ system
contains many different organs that cooperate to carry out a general process, such as the digestion of food
Body cavities
vertebrates have 2 main ___ _____; smaller dorsal & larger ventral
Skin
2 main regions: epidermis and dermis
Subcutaneous layer
AKA hypodermis; found between the skin and any underlying structures, such as muscle or bone
Epidermis
made up of stratified squamous epithelium; can be thin or thick
Melanocytes
specialized cells in the epidermis that produce melanin, the pigment responsible for skin color
Dermis
region of dense fibrous connective tissue beneath the epidermis; contains collagen and elastic fibers
Nails
protective covering of the distal part of the fingers and toes, collectively called digits; grow from special epithelial cells at the base of these in the portion called the ___ root
Hair follicles
begin in the dermis and continue throughout the epidermis, where the hair shaft extends beyond the skin
Oil glands
AKA sebaceous glands; secrete sebum, an oily substance that lubricates the hair within the follicle and the skin itself
Sweat glands
present in all regions of skin; on average, a person’s skin has about 250,000 of these; tubules that begin in the dermis and either open into a hair follicle, or more often, opens onto the surface of the skin; play a role in modifying body temperature
Homeostasis
ability of an organism to maintain a relatively constant internal environment
Poikilothermic
cold-blooded; body temperature fluctuates depending on environmental temperature; saves energy but restricts the ability of the species to live in extremely cold or hot environments
Homeothermic
warm-blooded; birds and mammals have mechanisms for regulating their body temperature toward an optimum; energetically expensive but provides the evolutionary advantage of being able to adapt to many different environments
Negative feedback
primary homeostatic mechanism that keeps a variable, such as the blood glucose level, close to a particular value, or set point
Positive feedback
mechanism that brings about a continually greater change in the same direction (ex. contractions in child birth)
