Chapter 20 Unifying Concepts of Animal
Structure and Function
1) Structure fits function in the animal body
a) Anatomy (structure) – the study of the structure of an
organism
i)
arrangement of muscles and bones
ii) structures of the digestive system
b) physiology (function) – the study of the functions an
organism performs
i)
the functioning of muscles
ii) functions of the digestive system
c) Example – flight apparatus of birds
i)
feathers
(1) feathers –
(a)function
give broad shape without adding much weight
(ii) remain dry due to oil coating
(iii)trap air to maintain body temp and metabolism
(i)
(b)
structure
(i) consist of non-living material (mainly
protein keratin)
(ii) hollow shaft
1.
2.
3.
strong with minimal weight
barbs form vane of the feather
barbules extend from barbs
a. tiny hooks that interlock with adjacent
barbules
b. gives feather shape and rigidity
c. when they detach, feather is lost and flight
impaired
d. birds preen – draws feathers through beaks
rehooking barbs (rezips)
d) bottom line – structure fits function
2) Animal structure has a hierarchy
a) cellular level: muscle cell
b) tissue level: many muscle cells working together
c) organ level: group of tissues that perform a specific
function(s) - heart
d) organ system level: circulatory system
e) organism level: group of organ systems working together to
make a complete organism
3) Tissues are groups of cells with a common structure and
function
a) tissue – (latin for “weave”)cooperative unit of many similar
cells performing a special function
i)
most cells of multicellular organisms are organized
into tissues
ii) the cells themselves are highly specialized to perform
their function
iii) Cells are held together by
(1) nonliving fibers
(2) sticky coating around cells
(3) cell junctions (tight, anchoring, communication)
iv) 4 major categories
(1) epithelial – covers and lines the body and its parts
(a)simple vs. stratified
(b) squamous vs. cuboidal vs. columnar
(c)structure fits function (obviously)
(2) connective
(a)cells are sparse and scattered through an ECM like
raisons in bread
cells produce the ECM, which is a web of fibers in a
jelly (like if raisons were to make the bread)
(c)Six types (First three have loose matrices (soft,
mushy bread – fresh out of the oven; the last three
have hard matrices – two week old bread)
(i) Loose connective tissue
1. loose weave fibers (many collagen)
2. like packaging material (Styrofoam peanuts) –
holds other tissues and organs in place
(ii) Adipose tissue
1. fat storage
2. pads and insulates body, stores energy
(iii)Blood
1. fluid rather than solid matrix called PLASMA
2. plasma
a. water
b. salts
c. dissolved proteins
3. RBCs and WBCs are suspended in plasma
4. transports substances in body and immunity
(iv) Fibrous connective tissue
1. densely packed parallel collagen fibers
2. forms
a. tendons – attach muscle to bone
b. ligaments – attach bones together
(v) Cartilage
1. abundance of collagen in a rubbery substance
2. flexible skeletal material
3. ends of bones, nose, ears, cushioning discs b/w
vertebrae
(vi) Bone
1. rigid connective tissue
2. collagen fibers embedded in calcium salts
a. calcium alone would be hard, but brittle
b. like reinforced concrete
(b)
c. bone-making cells are fed through central
canals with blood vessels
(3) muscle
(a)made
up of muscle fibers
(b) most abundant tissue type in animals
(c)3 types in vertebrates
(i) skeletal
1. attached to bones by tendons
2. voluntary
3. light and dark bands – striated (striped) –
functional units
4. fixed number in adults, can grow in size
(ii) cardiac
1. contractile tissue of heart
2. striated
3. branched cells
4. ends of cells joined by communication
junctions to allow cells to signal each other
5. involuntary
(iii)smooth
1. lack of striations…hence smooth
2. walls of digestive tract, urinary bladder,
arteries and other internal organs
3. spindle shape
4. slow endurance cells – contract slow but can
sustain for long time unlike skeletal
5. involuntary
(4) nervous
(a)forms a rapid communication system
(b) senses stimuli, processes and directs response
(c)neuron = a single nerve cell
(i) specialized to conduct signals
(ii) cell body, dendrites and axon
(iii)axon can be a meter or more long
transmission from one place to another usually
involves a chain of neurons
(e)neurotransmitters allow cells to talk to each other
(f) many other non-neural cells make up nervous tissue
1. schwann cells – wrap neurons and insulate
2. glial cells – provide support and nutrition
(d)
4) Several tissues are organized to form an organ (organ = group
of tissues working together to perform a specific function(s)).
a) Example: small intestines
i)
columnar epithelium – lines lumen, secretes mucous
and digestive juices (enzymes)
(1) villi – fingerlike projections – increase surface area for
more efficient digestion
ii) connective tissue – loose connective tissue – contains
nerves and blood vessels
iii) Smooth muscle layers (2) – move food through
digestive tract (peristalsis)
iv) Another layer of connective tissue
b) Bottom line: tissues cooperate and new levels of structure
and function are achieved
5) The body is a cooperative of organ systems
a) organ system – group of organs that work together to perform
vital life functions
b) Twelve major organ systems in vertebrates
i)
Digestive system
ii) Respiratory system
iii) circulatory system
iv) lymphatic system
v)
immune system
vi) excretory system
vii) endocrine system
viii) reproductive system
ix)
x)
xi)
xii)
nervous system
muscular system
skeletal system
integumentary system