Key terms
101 terms- Tissue§41.1
- Similar cells of common embryonic origin performing one function
- Organ§41.1
- Discrete structure built from several tissue types acting as one unit
- Organ system§41.1
- Group of organs cooperating on a major body function
- Diploblastic§41.1
- Having two germ layers — endoderm and ectoderm only (cnidarians)
- Triploblastic§41.1
- Having three germ layers; mesoderm added, enabling many more tissue types
- Mesoglea§41.1
- Cnidarian middle layer; hydrostatic skeleton holding muscle and nerve bundles
- Epithelial tissue§41.2
- Sheets of tightly joined cells lining, covering, and forming glands
- Apical surface§41.2
- The free epithelial face, exposed to the outside or to a lumen
- Basement membrane§41.2
- Protein-fiber and glycoprotein mat anchoring epithelium to connective tissue
- Tight junction§41.2
- Sealing junction that binds epithelial cells into a barrier
- Desmosome§41.2
- Adhesive junction linked to intermediate filaments
- Gap junction§41.2
- Communicating channel letting ions and small molecules pass between cells
- Simple epithelium§41.2
- One cell layer; every cell touches the basement membrane
- Stratified epithelium§41.2
- Two or more cell layers; only the basal layer touches the basement membrane
- Pseudostratified epithelium§41.2
- Looks layered but is one layer; not all cells reach the free surface
- Squamous§41.2
- Flattened cell shape with no clean geometry
- Cuboidal§41.2
- Cell whose height about equals its width
- Columnar§41.2
- Cell taller than it is wide
- Keratin§41.2
- Protective protein loaded into the outer layers of stratified squamous skin
- Gland§41.2
- Epithelium specialized to manufacture and secrete products
- Exocrine gland§41.2
- Secretes through a duct to the target (sweat, salivary)
- Endocrine gland§41.2
- Secretes into the blood for delivery elsewhere (thyroid, pituitary)
- Goblet cell§41.2
- Unicellular exocrine gland secreting mucus in gut and airway
- Connective tissue§41.3
- Sparse cells embedded in abundant extracellular matrix; mesodermal origin
- Matrix§41.3
- Extracellular protein fibers plus ground substance
- Ground substance§41.3
- The non-fiber, often fluid component of the matrix
- Fibroblast§41.3
- Cell that makes and secretes the matrix of connective tissue proper
- Collagen§41.3
- Fiber forming the supporting meshwork of the matrix
- Elastin§41.3
- Fiber conferring elasticity on the matrix
- Reticulin§41.3
- Fiber propping up the collagen network
- Mast cell§41.3
- Immune cell resident in loose connective tissue
- Macrophage§41.3
- Phagocytic immune cell resident in loose connective tissue
- Adipose tissue§41.3
- Densely clustered fat cells storing triglyceride droplets
- Dense regular connective tissue§41.3
- Parallel collagen; builds tendons and ligaments
- Dense irregular connective tissue§41.3
- Multidirectional collagen; forms organ capsules and sheaths
- Tendon§41.3
- Dense regular connective tissue attaching muscle to bone
- Ligament§41.3
- Dense regular connective tissue attaching bone to bone
- Chondroitin§41.3
- Glycoprotein forming the ground substance of cartilage
- Hyaline cartilage§41.3
- Mature cartilage tightly packed with parallel collagen
- Chondrocyte§41.3
- Cartilage cell, housed in a lacuna
- Lacuna§41.3
- Small space in cartilage matrix that holds a chondrocyte
- Osteocyte§41.3
- Bone cell living inside the calcified matrix
- Canaliculi§41.3
- Tiny channels through which osteocyte processes connect to neighbors
- Central canal§41.3
- Bone channel carrying blood vessels to feed osteocytes
- Erythrocyte§41.3
- Red blood cell
- Leukocyte§41.3
- White blood cell
- Thrombocyte (platelet)§41.3
- Clotting cell fragment derived from a bone marrow cell
- Plasma§41.3
- The liquid extracellular matrix of blood
- Smooth muscle§41.4
- Unstriated, involuntary, spindle-shaped visceral muscle with one nucleus
- Striated muscle§41.4
- Banded muscle whose contractile proteins are highly ordered
- Skeletal muscle§41.4
- Voluntary striated muscle of long multinucleate fibers
- Muscle fiber§41.4
- Long multinucleate skeletal muscle cell formed by cell fusion
- Myofibril§41.4
- Contractile element inside a skeletal muscle fiber
- Cardiac muscle§41.4
- Striated, vertebrate-heart-only muscle of small interconnected cells
- Intercalated disk§41.4
- Gap-junction-rich junction joining cardiac cells into one functional unit
- Myosin§41.4
- Contractile protein present even in sponges, before true muscle evolved
- Viscera§41.4
- The internal organs, where smooth muscle is found
- Neuron§41.5
- Nerve cell that generates and conducts electrochemical impulses
- Dendrite§41.5
- Branched extension carrying impulses toward the neuron cell body
- Axon§41.5
- Single extension carrying impulses away from the cell body
- Neuroglia (glial cells)§41.5
- Non-conducting cells that support, nourish, and protect neurons
- Neuromuscular junction§41.5
- Site where an axon meets muscle fibers
- Musculoskeletal system§41.6
- Muscles plus the skeleton they pull against
- Hydrostatic skeleton§41.6
- Fluid-based support framework, as in an earthworm
- Integumentary system§41.6
- Skin, hair, and nails — the first barrier of defense
- Zygote§41.6
- Diploid cell formed by the fusion of two gametes
- Homeostasis§41.7
- Dynamic constancy of the internal environment
- Negative feedback§41.7
- Control loop in which the output restrains the process producing it
- Set point§41.7
- The target value a homeostatic system defends
- Sensor§41.7
- Cell or receptor that detects a deviation from set point
- Integrating center§41.7
- Comparator that checks conditions against the set point (often hypothalamus)
- Effector§41.7
- Muscle or gland whose action corrects the deviation
- Antagonistic effectors§41.7
- Paired opposite-acting effectors giving push-pull control
- Positive feedback§41.7
- Amplifying loop that drives a value farther from set point
- Oxytocin§41.7
- Pituitary hormone driving the positive feedback loop of childbirth
- Q10§41.8
- Ratio of reaction rates 10 °C apart; R(T+10)/R(T)
- Radiation§41.8
- Contactless heat transfer by electromagnetic waves
- Conduction§41.8
- Heat transfer between objects in direct contact
- Convection§41.8
- Heat carried away by a moving gas or liquid
- Heat of vaporization§41.8
- Energy needed to turn liquid into gas; high for water, used in cooling
- Homeotherm§41.8
- Animal holding a constant regulated body temperature
- Poikilotherm§41.8
- Animal whose body temperature conforms to the environment
- Endotherm§41.8
- Animal that uses metabolism to generate heat and stay above ambient
- Ectotherm§41.8
- Animal with low metabolic rate that does not use metabolism for heat
- Heterotherm§41.8
- Animal intermediate between endotherm and ectotherm
- Countercurrent heat exchange§41.8
- Vessel arrangement that rewarms returning venous blood from adjacent arteries
- Vasodilation§41.8
- Widening of surface vessels to increase heat loss
- Vasoconstriction§41.8
- Narrowing of surface vessels to reduce heat loss
- Evaporative cooling§41.8
- Heat loss by sweating or panting
- Thermogenesis§41.8
- Metabolic heat production below a critical low temperature
- Shivering thermogenesis§41.8
- Heat from antagonistic muscles contracting against each other
- Nonshivering thermogenesis§41.8
- Heat from fat metabolism rerouted away from ATP production
- Brown adipose tissue (BAT)§41.8
- UCP1-rich fat that produces heat instead of ATP
- UCP1§41.8
- Proton-leak channel uncoupling electron transport from ATP synthesis
- Beige fat§41.8
- White adipose tissue convertible into brown adipose tissue
- Thyroxine§41.8
- Thyroid hormone that stimulates metabolism; driven by pituitary TSH
- Pyrogen§41.8
- Substance that raises the hypothalamic set point, producing fever
- Torpor§41.8
- Dormant state with lowered metabolic rate and body temperature
- Hibernation§41.8
- Deep torpor lasting weeks to months, up to 20 °C below set point
- Winter sleep§41.8
- The bear pattern — long dormancy with only a few degrees of cooling
- Mouse-to-elephant curve§41.8
- Plot showing mass-specific metabolic rate falls sharply with body size