Chapter 42 Flashcards
The vertebrate body has what four levels of organization?
cells, tissues, organs, organ systems
Humans have how many different types of cells?
210 different types of cells
What are tissues?
groups of cells that are similar in structure and function
Early in development, cells of the growing embryo differentiate into three fundamental embryonic tissues, which are called
germ layers
What are the four primary tissues in adults?
epithelial, connective, muscle, nerve
What are organs?
body structures composed of several different types of tissues that form a structural and functional unit
What is an organ system?
group of organs that cooperate to perform the major activities of the body
What is the inner tube of vertebrates?
the digestive tract, which runs from the mouth to the anus
What supports the outer tube of vertebrates?
internal skeleton made of jointed bones or cartilage
What is the outermost layer of the vertebrate body?
integument (skin) + accessories, such as hair/feathers/scales/sweat glands
How many identifiable cavities are there in the main vertebrate body?
two
What is the dorsal body cavity?
forms within a bony skull and a column of bones (vertebrae)
What is the ventral body cavity?
extends anteriorly from the area bounded by the rib cage and vertebral column posteriorly to the area contained within the ventral body muscles (abdominals) and the pelvic girdle
What is the thoracic cavity?
contains the heart and lungs
What is the abdominopelvic cavity?
contains many organs including the stomach, intestines, liver, kidneys, and urinary bladder
The ventral body cavity is broken by the diaphragm
anteriorly into the thoracic cavity and posteriorly into the abdominopelvic cavity
What is a coelom?
fluid-filled body cavity completely formed within the embryonic mesoderm layer of some animals
Contrast the coelom in vertebrates and invertebrates.
Compared to invertebrates, the coelom in vertebrates is constricted, folded, and subdivided
In the abdominopelvic cavity, the coelomic space is called the
peritoneal cavity
What is the pericardial cavity?
space within the mesodermal layers around the heart
What are the pleural cavities?
thin spaces around the lungs
What is the epithelium?
membrane that covers every surface of the vertebrate body
Epithelial membranes are derived from
any of the three germ layers
The three germ layers, from innermost to outermost, are
endoderm, mesoderm, ectoderm
For land vertebrates, why is the impermeability of the epidermis important?
it offers essential protection from dehydration and airborne pathogens
How does the epithelial lining of the digestive tract function as a barrier?
allows for the selective entry of the products of digestion while providing a barrier to toxic substances
How does the epithelium of the lungs function as a barrier?
allows for the rapid diffusion of gases into and out of blood
What is a characteristic of all epithelia in terms of spatial arrangement?
all epithelial cells are tightly bound together, with very little space between them
How thick are most epithelial membranes?
one or a few cell layers thick
Give an example of a gland made of epithelial tissue that can readily regenerate.
the liver
How often is the epidermis renewed?
every two weeks
How often is the epithelium inside the stomach renewed?
every two to three days
Why is epithelial regeneration important?
it constantly renews the surface and also allows quick replacement of the protective layer should damage or injury occur
How do epithelial tissues attach to underlying connective tissues?
by a fibrous membrane
The secured side of the epithelium is called
basal surface
The free side of the epithelium is called
apical surface
Why is having a basal/apical surface important for epithelial tissues?
it gives the tissues an inherent polarity
What are the two general classes of epithelial membranes?
simple (single layer of cells) and stratified (multiple layers of cells)
What kind of cells are flat?
squamous cells
What kind of cells are about as wide as they are tall?
cuboidal cells
What kind of cells are taller than they are wide?
columnar cells
How thick are simple epithelial membranes?
one cell thick
What are simple squamous membranes composed of?
squamous epithelial cells
Where can simple squamous epithelia be found? (2)
lungs, blood capillaries
Where can simple cuboidal epithelia be found? (2)
kidney tubules, several glands
Where can simple columnar epithelia be found?
airways of the respiratory tract, inside of most of the gastrointestinal tract
What are goblet cells?
specialized cells to secrete mucus that are interspersed among columnar epithelial cells of mucous membranes
The apical surface of columnar epithelial cells of the respiratory airways contains
cilia, which move mucus and dust particles toward the throat
The apical surface of columnar epithelial cells in the small intestine contains
microvilli, which increase the surface area for food absorption
The glands of vertebrates form from
invaginated epithelia
What is an exocrine gland?
gland that releases its secretion through a duct, such as a sweat gland or a digestive gland
How does the exocrine gland work?
The duct channels the product of the gland to the surface of the epithelial membrane and thus to the external environment
Give three examples of exocrine glands.
sweat, sebaceous, salivary glands
What are endocrine glands?
ductless glands; connections with the epithelium from which they are derived are lost during development
Where do hormones secreted by the endocrine gland go?
hormones enter blood capillaries and circulate throughout the body instead of going to an epithelial membrane
How thick are stratified epithelial membranes?
two to several cell layers thick
How are stratified epithelial membranes named?
they are named according to features of their apical cell layers
The epidermis is what type of membrane?
stratified squamous epithelium
In terrestrial vertebrates, the epidermis is further characterized as
a keratinized epithelium because its upper layer consists of dead squamous cells and is filled with a water-resistant protein called keratin
What increases the deposition of keratin in the skin?
repeated abrasion (which causes calluses)
The water-resistant property of keratin is evident when comparing
the skin to the lips, because the lips are covered by a nonkeratinized stratified squamous epithelium that can easily become dried/chapped
What are the four types of simple epithelium?
squamous, cuboidal, columnar, pseudostratified columnar
What is the one type of stratified epithelium?
squamous
What is the typical location of simple squamous epithelium? (3)
lining of lungs, capillary walls, blood vessels
What is the function of the simple squamous epithelium?
cells form thin layer across which diffusion can readily occur
What are characteristic cell types of simple squamous epithelium? (1)
epithelial cells
What is the typical location of simple cuboidal epithelium? (2)
lining of some glands/kidney tubules; covering of ovaries
What is the function of simple cuboidal epithelium? (2)
cells rich in specific transport channels; functions in secretion and absorption
What are characteristic cell types of simple cuboidal epithelium?
gland cells
What is the typical location of simple columnar epithelium? (2)
surface lining of stomach, intestines; parts of respiratory tract
What is the function of simple columnar epithelium?
thicker cell layer; provides protection and functions in secretion and absorption
What are characteristic cell types of simple columnar epithelium?
epithelial cells
What is the typical location of simple pseudostratified columnar epithelium?
lining of parts of the respiratory tract
What is the function of simple pseudostratified columnar epithelium? (3)
secretes mucus; dense with cilia that aid in movement of mucus; provides protection
What are the characteristic cell types of simple pseudostratified columnar epithelium?
gland cells; ciliated epithelial cells
What is the typical location of stratified squamous epithelium? (2)
outer layer of skin; lining of mouth
What is the function of stratified squamous epithelium?
tough layer of cells; provides protection
What are the characteristic cell types of stratified squamous epithelium?
epithelial cells
Where do connective tissues derive from?
embryonic mesoderm
What are the two major classes of connective tissues?
connective tissue proper; special connective tissues
What are the two further divisions of connective tissue proper?
loose connective tissue; dense connective tissue
What are the three types of special connective tissue?
cartilage, blood, bone
What is the common structural feature of connective tissue?
all have abundant extracellular material because their cells are spaced widely apart
The extracellular material in connective tissue is called
the matrix
What does bone matrix do?
contains crystals that make the bones hard
What is the blood matrix?
plasma, the fluid portion of the blood
The matrix of connective tissue consists of
protein fibers and ground substance
What is ground substance?
the fluid material between cells and fibers containing a diverse array of proteins and polysaccharides
During the development of loose/dense connective tissue, what produces and secretes the extracellular matrix?
fibroblasts
Loose connective tissue contains what immune system cells? (2)
mast cells and macrophages
Loose connective tissue consists of
cells scattered within a matrix that contains a large amount of ground substance
How is the ground substance of loose connective tissue strengthened?
strengthened by a loose scattering of collagen, elastin, and reticulin
How does collagen increase the strength of the ground substance of loose connective tissue?
supports the tissue by forming a meshwork
How does elastin increase the strength of the ground substance of loose connective tissue?
makes the tissue elastic
How does reticulin increase the strength of the ground substance of loose connective tissue?
supports the network of collagen
Gelatin in desserts consists of
extracellular material extracted from the loose connective tissue of animals
What is another name for adipose cells?
fat cells
Why are adipose cells important?
important for nutrient storage
Where do adipose cells occur?
loose connective tissue
What is adipose tissue?
large groups of adipose cells
Where does adipose tissue develop? (3)
under the skin, in bone marrow, around the kidneys
Each adipose cell contains
a droplet of triglycerides within a storage vesicle
When adipose cells are needed for energy, what happens?
adipose cell hydrolyzes its stored triglyceride and secretes fatty acids into the blood for oxidation by the cells of the muscles/liver/other organs
Can adipose cells divide?
no, the number of adipose cells in an adult is fixed
When a person gains weight, how do adipose cells change?
adipose cells become larger
When a person loses weight, how do adipose cells change?
adipose cells shrink
Does dense connective tissue have more or less ground substance than loose connective tissue?
less ground substance
Is dense connective tissue more strong than loose connective tissue?
Yes, dense connective tissue is stronger than loose connective tissue
Dense connective tissue primarily contains
tightly packed collagen fibers
What are the two types of dense connective tissue?
regular and irregular
What are the collagen fibers in dense regular connective tissue like?
the fibers line up in parallel
Give an example of dense regular connective tissue.
tendons
What are the collagen fibers in dense irregular connective tissue like?
have many different orientations
Where can dense irregular connective tissue be found?
tough coverings that package organs, such as the capsules of the kidneys and the adrenal glands
What is the typical location of loose connective tissue? (2)
beneath skin; between organs
What is the function of loose connective tissue? (5)
provides support/insulation/food/storage/nourishment for epithelium
What are characteristic cell types of loose connective tissues? (4)
fibroblasts; macrophages; mast cells; fat cells
What is the typical location of dense connective tissue? (5)
tendons; sheath around muscles; kidney; liver; dermis of skin
What is the function of dense connective tissue?
provides flexible, strong connections
What are characteristic cell types of dense connective tissue?
fibroblasts
What s the typical location of cartilage? (5)
spinal disks; knees and other joints; ear; nose; tracheal rings
What is the function of cartilage? (3)
provides flexible support, shock absorption, reduction of friction on load-bearing surfaces
What are characteristic cel types of cartilage?
chondrocytes
What is the typical location of bone?
most of skeleton
What is the function of bone? (2)
protects internal organs; provides rigid support for muscle attachments
What are characteristic cell types of bones?
osteocytes
What is the typical location of blood?
circulatory system
What is the function of blood? (3)
functions as highway of immune systems; carries nutrients and waste; primary means of communication between organs
What are characteristic cell types of blood? (2)
erythrocytes, leukocytes
The ground substance in cartilage forms from
a type of glycoprotein called chondroitin
Describe the strength of cartilage. (4)
firm/flexible; does not stretch; tougher than either loose or dense connective tissue; has great tensile strength
Cartilage makes up the entire skeleton of which animals? (2)
modern agnathans and cartilaginous fishes
In adult vertebrates, where is cartilage mostly found? (5)
joint surfaces of bones; tip of the nose; outer ear; backbone disks; larynx
Where do chondrocytes live?
within spaces called lacunae within the cartilage ground substance?
What are lacunae?
spaces within the ground substance of cartilage within which chondrocytes live
How do chondrocytes in lacunae stay alive?
they receive oxygen and nutrients by diffusion through the cartilage ground substance from surrounding blood vessels
What is another name for bone cells?
osteocytes
The extracellular matrix in bones becomes hardened because of
crystals with calcium phosphate
What are canaliculi?
tiny canals through which osteocytes extend cytoplasmic processes toward neighboring osteocytes
In the course of fetal development, how do appendages form?
first modeled in cartilage, but then the cartilage matrix calcifies and living bone replaces the dying/degenerating cartilage
What is another name for red blood cells?
erythrocytes
What is another name for white blood cells?
leukocytes
What is another name for platelets?
thrombocytes
What makes muscle cells unique?
relative abundance and organization of actin and myosin filaments within them
What are the three kinds of muscle?
smooth, skeletal, and cardiac
What are the two striated muscles?
skeletal and cardiac muscles
Which two muscles are involuntary?
cardiac and smooth muscles
What was the earliest form of muscle to evolve?
smooth muscle
In vertebrates, where does smooth muscle occur?
viscera
What is another name for smooth muscle?
visceral muscle
Smooth muscle tissue is arranged into
sheets of long, spindle-shaped cells, with each cell containing a single nucleus
Skeletal muscles are usually attached to
bones by tendons
Skeletal muscle is made up of
long muscle cells called muscle fibers, which have multiple nuclei
What neuron stimulates muscle fibers?
motor neurons
Each muscle fiber contracts by means of substructures called
myofibrils, which contain highly ordered arrays of actin and myosin myofilaments
What is responsible for giving muscle fiber its striated appearance?
actin and myosin myofilaments
How are skeletal muscle fibers produced?
by the fusion of several cells, end-to-end (which is why they have multiple nuclei)
Cardiac muscle consists of
smaller, interconnected cells, each with a single nucleus
What are intercalated disks?
interconnections between adjacent cardiac cells that appear as a dark line under a microscope
The dark lines of intercalated disks are actually
regions where gap junctions link adjacent cells
The interconnections in cardiac muscle enable cardiac muscle cells to
form as a single functioning unit
What usually regulates the rate of impulse activity in cardiac muscle?
the nervous system
What is the typical location of smooth muscle? (3)
walls of blood vessels, stomach, and intestines
What is the function of smooth muscle?
powers rhythmic, involuntary contractions commanded by the central nervous system
What is the typical location of skeletal muscle?
voluntary muscles
What is the function of skeletal muscles?
powers walking, lifting, talking, and all voluntary movement
What is the function of cardiac muscle? (2)
highly interconnected cells; promotes rapid spread of signal initiating contraction
What are the two major types of cells in nerve tissue?
neurons and neuroglia
Generally speaking, neurons are specialized to
produce and conduct electrochemical events (impulses)
Neurons consist of what three parts?
a cell body, dendrites, and an axon
What contains the nucleus of a neuron?
the cell body
What are dendrites?
thin, highly branched extensions that receive incoming stimulation and conduct electrical impulses to the cell body
What is the axon?
single extension of the cytoplasm that conducts impulses away from the cell body
What do neuroglia do?
do not conduct impulses, but instead support and insulate neurons and eliminate foreign materials in and around neurons
Neuroglia cells associate with axons to produce
an insulating covering called a myelin sheath
How is a myelin sheath produced?
produced by successive wrapping of the membranes around the axon
Gaps in the myelin sheath are known as
nodes of Ranvier
What is the purpose of nodes of Ranvier?
serve as sites for accelerating an impulse
The nervous system is divided into what 2 domains?
the central nervous system (CNS) and the peripheral nervous system (PNS)
The central nervous system includes (2)
the brain and the spinal cord
The peripheral nervous system includes (2)
nerves and ganglia
Nerves consist of
axons in the PNS that are bundled to gether
Ganglia are collections of
neuron cell bodies
The CNS is generally responsible for
integrating and interpreting input, such as the input from the senses
The PNS is generally responsible for
communicating signals to and from the CNS and to the rest of the body
What is the typical location of sensory neurons? (3)
eyes; ears; surface of skin
What is the function of sensory neurons? (2)
receive information about the body’s condition and external environment; send impulses from sensory receptors to the CNS
What are characteristic cell types of sensory neurons? (2)
rods + cones; muscle stretch receptors
What is the typical location of motor neurons? (2)
brain and spinal cord; axons extending through the body
What is the function of motor neurons? (2)
stimulate muscles and glands; conduct impulses out of the CNS toward muscles and glands
What are the characteristic cell types of motor neurons?
motor neurons
What is the typical location of interneurons? (2)
brain and spinal cord
What is the function of interneurons? (2)
integrate information; conduct impulses between neurons within CNS
What are the characteristic cell types of interneurons?
interneurons
The general nervous system consists of (4)
brain, spinal cord, nerves, sensory organs
What is the relationship between the sensory and nervous systems?
the sensory system is a subset of the nervous system
What does the endocrine system do?
issues chemical signals that regulate and fine-tune chemical processes taking place in other organ systems
The musculoskeletal system consists of what two interrelated organ systems?
muscular system + skeletal system
The digestive system is responsible for
absorbing nutrients and eliminating solid wastes
The circulatory system is responsible for (2)
pumping and distributing blood; carrying nutrients and other substances throughout the body
The respiratory system is responsible for (2)
acquiring oxygen and expelling carbon dioxide
The urinary system is responsible for
tightly regulating the concentration of bodily fluids
What is the body’s first line of defense against external threats?
integumentary system
What is the integumentary system?
intact skin
What is the body’s second line of defense against external threats?
immune system
What is formed when gametes fuse?
zygote
Specialization of cell function is only possible when
extracellular conditions stay within narrow limits, including things like temperature/pH
What is homeostasis?
dynamic constancy of the internal environment
How does negative feedback work?
if conditions deviate too far from a set point, biochemical reactions are initiated to change conditions back toward the set point
What is the set point?
the normal, existing point (analogous to the temperature setting on a thermostat)
What is the stimulus?
deviation from a set point
What is the sensor?
constantly monitors conditions
What is the integrating center?
compares conditions to a set point based on a desired value
What is the effector?
causes change to compensate for deviation
What is the response?
move system towards set point
Draw out the diagram at the top of page 876.
draw
What is the standard human body temperature?
98.6 F
What part of the brain is responsible for monitoring body temperature?
the hypothalamus
How does the hypothalamus respond to increases in body temperature? (2)
promotes the dissipation of heat through sweating; dilation of blood vessels
What is the purpose of antagonistic effectors?
affords a finer degree of control than by simply switching one effector on and off
Give two examples of positive feedback mechanisms.
blood clotting, childbirth
What is Q10?
the ratio between rates of a reaction at two temperatures that differ by 10 C
What is the equation for Q10? (pg. 877)
write out
For most enzymes, the Q10 value is
2, which means for every 10 C increase in temperature, the reaction rate doubles
Most organisms have a Q10 metabolic rate of
2 or 3
In some intertidal invertebrates, the Q10 metabolic value is
1
Body heat =
heat produced + heat transferred
What is radiation?
the transfer of heat by electromagnetic radiation, such as from the Sun
Does radiation require direct contact?
no
Heat transferred from hotter bodies to colder bodies is transferred via
radiation
What is conduction?
the direct transfer of heat between two objects, usually from a hotter object to a colder object
What is convection?
the transfer of heat by the movement of a gas or liquid
Animals that regulated their body temperature about a set point were called
homeotherms
Animals that allowed their body temperature to conform to the environment were called
poikilotherms
Homeotherms were colloquially called
warm-blooded
Poikilotherms were colloquially called
cold blooded
What are endotherms?
animals that use metabolism to generate body heat and maintain their temperatures above the ambient temperature
What are ectotherms?
animals with a relatively low metabolic rate that do not use metabolism to produce heat
Which type of therm has a lower thermal conductivity?
endotherms, because of insulating mechanisms
What are heterotherms?
animals that lie between endotherms and exotherms
What is countercurrent heat exchange?
allows the cooler blood in the veins to be warmed through the radiation of heat from the warmer blood in the arteries
Countercurrent heat exchange can be found in which animals?
tuna, swordfish, and some sharks
Which type of therm has low metabolic rates?
ectotherms
What are the advantages and disadvantages of being an ectotherm?
advantage is that they only need a low intake of energy, but are not capable of sustaining high-energy activity
Dilating blood vessels has what effect on heat dissipation?
the dilation of blood vessels increases heat dissipation
What is thermogenesis?
the use of normal energy metabolism to produce heat
What are the two forms of thermogenesis?
shivering and non-shivering
What happens in non-shivering thermogenesis? (3)
fat metabolism is altered to produce heat instead of ATP; takes place throughout the body; stored in brown fat in some mammals
What happens in shivering thermogenesis? (2)
uses muscles to generate heat without producing useful work; involves the use of antagonistic muscles to produce little net movement but hydrolysis of ATP which generates heat
Describe the sequence of events that occurs when the hypothalamus detects a temperature increase. (5)
neurons in hypothalamus detect change; leads to stimulation of heat-losing center in hypothalamus; nerves cause dilation of peripheral blood vessels; other nerves stimulate production of sweat; production of hormones that stimulate metabolism is inhibited
Describe the sequence of events that occurs when the hypothalamus detects a temperature drop. (4)
antagonistic effects are produced by hypothalamus; under control of heat-promoting center; nerves constrict blood vessels and discourage sweating; adrenal medulla produces epinephrine + anterior pituitary produces TSH, which both stimulate metabolism
What is a pyrogen?
a substance that causes a rise in temperature
What is fever?
a result of resetting the body’s normal set point to a higher temperature
What kind of bacteria are host to pyrogens?
gram-negative bacteria have components in their cell walls called endotoxins that act as pyrogens
Pyrogens act on what?
the hypothalamus
How can fevers be beneficial?
higher temperatures can inhibit bacteria growth
What is torpor?
a state of dormancy that results when endotherms reduce metabolic rate and body temperature
How is torpor useful?
reduces the need for food intake because torpor reduces metabolism
What is hibernation?
an extreme state of torpor that can last for months
