Download Chapter 2 Tissues

chapter 2
Tissue Types and Functions
Tissues
Describe the properties, locations, functions, and
varieties of the 4 different tissue types.
Tissue - a collection of cells organized for
a particular function
Mammals have 4 types: epithelial,
connective, muscle, nerve.
Epithelial
Properties & Location
collections of cells
packed together in
sheets
lines body surface
& openings, blood
vessels, and heart
epithelial
Functions:
protection: from......
trauma
UV light
temperature
bacteria
epithelial
Functions (cont):
Produce secretions:
tears & saliva
moisten
mucous traps dust
excretions like
urine & sweat
milk from
mammary cells
epithelial
Functions (cont):
Absorbs Materials:
cells lining lungs, intestines,
& kidneys absorb materials
from surrounding fluids
cells lining blood vessels
absorb from ECF
epithelial
Varieties:
Simple - one layer
Stratified - multiple
layers
Transitional - multiple
layers that change
shape
epithelial
Varieties:
Squamous - very flat
Cuboidal - cube
shaped
Columnar - more tall
than wide
Simple cuboidal
single layer of cube
shaped cells
associated with
secretion
Simple columnar
single layer of tall
narrow cells
associated with
absorption
Stratified squamous
multiple layers of flat
cells
skin
Transitional
change shape
urinary tract only
skin (integument)
Protection:
2 way barrier
body temperature
UV
pain, pressure,
temperature
Overall
health
first indication!
skin layers
epidermis - stratified
squamous, outermost
dermis - connective
layer containing
blood vessels,
nerves, & glands
subcutaneous - fatty
layer (hypodermis)
modifications
Hair: provides
insulation, protection,
sensation
originates from
follicle in dermis
shaft=epithelial
cells
Arrector pili: when
contracted hair
stands upright
modifications
Footpads/Digital pads
resists physical
trauma
acts as a cushion
Modifications
Claws
hardness &
durability
surround last bone
of toe
rich blood supply
around bone
nourishes claw
(quick)
modifications
Hooves
made of keratin
filled cells
(specialized
protein)
similar anatomy
modifications
Horns
keratinized
epithelium that
extends from skull
connective
Properties:
several types
produces matrix
fibrous or smooth
connective
Functions:
Connects, supports,
protects
connective
Functions (cont):
connect one organ or
tissue to another
tendons - muscle to
bone
ligaments - bone to
bone
example
deep laceration of
digital flexor tendon
(raised toe)
connective
Functions (cont):
support & protect
bone & cartilage
support
hold muscles
together
support organs
connective
Varieties:
tendons
ligaments
bone
adipose
blood
Muscle
Properties:
3 types of muscle
voluntary &
involuntary control
muscle
Location:
All throughout body!
muscle
Function:
skeletal - (voluntary)
attaches to skeleton,
allows movement
muscle
Function (cont)
smooth - (involuntary)
hollow organs &
blood vessels
movement of organs,
pumping of blood
muscle
Function (cont)
cardiac - (involuntary)
heart muscle
myocardial
contractions
muscle
Varieties:
skeletal
striated-consists of
thousands of
muscle cells
(myofibers)
myofibers have several nuclei and a large
number of mitochondria
myofilaments-organized system within
muscle fibers that control contractions
actin/myosin - proteins making up
myofilaments
contraction
during contractions,
actin/myosin slide
along one another
begins with
stimulation of nerve
cell
contractions
nerve impulse
stimulates Ca release
from storage in ER
Ca flow causes
filaments to slide
relaxation- cell
actively transports Ca
back into ER
clinical practice
Porcine Stress
Syndrome (PSS)
Ca is not transported
back into ER
muscles don’t relax
normally
clinical practice
RIGOR MORTIS
stiffness after death
no energy supply to
pump Ca back into
ER
muscles remain stiff
CLINICAL PRACTICE
MILK FEVER
calving time causes
low Ca
(hypocalcemia)
causes weakness
Cardiac muscle
involuntary
myofilaments similar
to skeletal
more mitochondria
no nerve impulse
required
pacemaker cells
control rate
smooth muscle
lacks striations
actin/myosin in
different arrangement
sheets around hollow
openings
slower contractions
longer contractions
smooth
nervous
Properties:
communication
nerve
cells=neurons
neuron
soma (body) houses
nucleus/organelles
axon carries impulses
to tissues/muscles
axon bundles =
nerves!
dendrites begin
impulse
NERVOUS
Location:
Central Nervous
System (CNS) =
brain/spinal cord
Peripheral Nervous
System (PNS) =
nerves extended
throughout body
nervous
Function:
carries electrical
impulses
nerve impulse
resting nerve cells =
Na ions are actively
transported into ECF
K is pumped into
cytoplasm
ions flow rapidly
across membrane
after stimulation
electrical event
nervous
Varieties:
Sensory neurons
Interneurons
Motor neurons
sensory neurons
receptors are
stimulated in
response to an
environmental
change
light, heat, touch,
hearing, balance,
taste, smell, internal
chemical receptor
interneurons
stimulated by sensory
neurons, found in
CNS
controls activity
motor neurons
cause an action to
occur
stimulated by sensory
or interneurons
begin in CNS, extend
to muscle or gland
environment stimulates sensory (outside
to in)
sensory stimulates interneurons (inside)
both stimulate motor neurons (inside to
out)
clinical practice
certain infectious diseases may infect specific
tissue types
foot & mouth disease
highly infectious,
rapid spread
usually not fatal,
serious signs
blisters in mouth &
tongue
epithelium around
hooves swell
injuries
connective tissue
damage often results
from injuries
fights, wildlife
encounters, hit by
car, abuse
skin may be
separated from
connective tissue
tying up
muscle tissue
damage
waste products leak
into bloodstream
kidney damage may
result
horners syndrome
nerve damage
nerve that controls
eye function is
damaged
pupil constriction,
drooping eyelid, third
eyelid protrudes,
sunken eye