Biology 107
Lecture Notes: Introduction to
animal structure and function.
Reading: Chapter
40 in text.
__________________________________________________________________
Anatomy = structure of an
organism
Physiology = function the structure performs
Includes
the study of how the ÒformÓ of a tissue is adapted to its function
Tissues
Groups of cells with common structure and function
Cells
are often held together by a sticky coating or woven together in a fabric of
extracellular fibers
Histology:
Four main categories of tissues:
1. Epithelial tissue
2. Connective tissue
3. Nervous tissue
4. Muscle tissue
Epithelial tissue
á
Formed from sheets of
tightly packed cells
á
Covers the outside of
the body and lines organs and organ cavities
á Its free surface is exposed to air or fluid. Cells at the base are attached to a basement membrane:
Categories of Epithelial
tissue:
o
Number of layers:
Simple epithelium :
Stratified epithelium:
o
Shape:
Cuboidal:
Columnar:
Squamous:
Connective tissue
á
Sparsely populated by
cells
á
Binds and supports other
tissues
á
Consists of loose weave
of three types of proteinaceous fibers:
o
Collagenous fibers:
o
Elastic fibers:
o Reticular fibers:
Types of connective tissue:
á
Loose connective
tissue
Two
cell types : Fibroblast:
Macrophages:
Has
all three fiber types
Binds
epithelia to underlying tissue and acts as packing material
á
Adipose tissue
á
Fibrous connective
tissue
á
Cartilage
Chondrocyte:
á
Bone - a mineralized connective tissue
Osteoblasts:
Haversian systems:
Osteocytes:
Lacunae:
Canaliculi:
Marrow:
á
Blood
Extracellular
matrix is plasma, which contains water, salts, and proteins
Cellular
components include:
Leukocytes:
Erythrocytes:
Platelets:
Interstitial fluid:
Nervous tissue
Made
of neurons:
Parts
of a neuron
Dendrites:
Axon:
Synapses:
Muscle tissue
Consists
of long, excitable cells capable of contraction
Actin:
Myosin:
There
are three types of vertebrate muscle tissue
á
Skeletal muscle Ð responsible for voluntary movement
o
striated muscle:
á
Cardiac muscle
o
Cells are striated and
branched
o
intercalated disks:
á Smooth muscle - is unstriated muscle
Tissues are organized into organs
In some organs, the tissues may be
layered (example = stomach)
Mesenteries:
Thoracic
cavity:
Abdominal cavity:
Organs may be organized into organ systems
Organ
system :
Body size and shape affect interactions with the
environment
o
There is a constraint on
animal size and shape
o
As cell size increases,
volume increases proportionately more than surface area
o
Complex, multicellular
organisms need internal exchange surfaces
Regulating the internal environment
Homeostasis:
Homeostasis depends on
feedback circuits
á
There are three
components to a feedback circuit
o
Receptor:
o
Control center:
o
Effector :
á
Negative feedback:
á
Positive feedback:
á
Set point :
Animal bioenergetics
á Animals are heterotrophs:
á Plants are autotrophs:
á Energy is extracted from food through digestion:
and catabolism:
Metabolic
rate = total amount of energy an animal uses per unit of time;
usually measured in calories or kilocalories (kcal = 1000 calories)
Endotherms =
o
Basal metabolic rate (BMR)=
Ectotherms =
o Standard metabolic rate=
There is an inverse
relationship between metabolic rate and size among similar animals.