Transcript 15 Tissues and Skin

Tissues and Integumentary
(Skin) System
Nestor T. Hilvano, M.D., M.P.H.
(Images Copyright Discover Biology, 5th ed., Singh-Cundy and Cain,
Textbook, 2012.)
Learning Objectives
1. Describe the 4 main types of tissues, noting their
structures, locations, functions and examples.
2. Describe the functions of the different organ
systems.
3. Differentiate the types of epithelial tissues as to
structure, function, and give an example for each.
4. Compare and contrast the 3 types of muscles.
5. Describe the nervous tissues.
6. Discuss the two main layers of the skin, including
it’s functions and appendages.
7. Discuss homeostasis and distinguish between
negative and positive feedback.
Overview of Structure and Function of
Organism
•
•
•
•
___ What is the study of structures or parts of
the body? ___ of function? ___ study of
tissues? a) histology b) anatomy c) microbiology d) anatomy
___ is a group of similar cells with a common
function.
___ is made up of several (different types)
tissues.
___ is composed of many organs that work
together to perform life functions.
a) organ system b) organ c) tissues d) organism
Systems (Organ-System)
– The digestive and respiratory systems
• Gather food and oxygen
– The circulatory system, aided by the lymphatic system
• Transports the food and oxygen
– The immune system
• Protects the body from infection and cancer
– The excretory system
• Disposes of certain wastes
– The endocrine and nervous systems
• Control body functions
– The integumentary system
• Covers and protects the body
– The skeletal and muscular systems
• Support and move the body
– The reproductive system
• Perpetuates the species
4 Main (Fundamental) Types of
Tissues
1.
2.
3.
4.
epithelial tissue
connective tissue
muscular tissue
nervous tissue
Epithelial Tissue
• Covers the body and lines its
organs and body cavities
• Common features/characteristics
of epithelium:
a) closely packed cells
b) lie on basement membrane
c) avascular
d) can be derived from 3 germ
layers (ectoderm, mesoderm, endoderm)
• Functions = protection, secretion,
absorption, filtration, sensory
receptor, excretion, lubrication.
Types of Epithelial
Tissues:
• __ 1 layer of cells.
• __ 2 or more
layers of cells.
• __ false layers of
cells (false
stratification).
a.
b.
c.
d.
Stratified epithelium
Pseudostratified epithelium
Simple epithelium
Transitional epithelium
Pseudostratified columnar
Simple Epithelium
• Simple squamous
- function: exchange of materials, diffusion, or
filtration
- example: endothelium of blood vessels, alveoli
of lungs
• Simple cuboidal
- function: absorption or secretion
- example: kidneys tubules (w/brush border= microvilli),
ducts of glands, thyroid follicles
• Simple columnar
- function: absorption or secretion
- example: digestive (GIT) tracts (w/ goblet cells,
striated border= microvilli)
Exercises: What is the fingerlike projections of cell membrane that
increases surface area for absorption?
a. cilia b. microvilli c. flagella d. gap junction
Stratified Squamous
• Stratified squamous
- several layers of cells, squamous
(flat) superficial cells
- function: protective barriers
• Stratified squamous nonkeratinized- outermost squamous
cells are alive, nucleated squamous
cells; found in oral cavity,
esophagus, vagina
• Stratifies squamous keratinized
(cornified)- outermost cells are
dead, non-nucleated cells, with
keratins; found in epidermis of skin
Pseudostratified Columnar
• Pseudostratified Columnar- false
layers of cells, with cilia on
surface and goblet cells;
protection, secretion, and
absorption
• Found in respiratory passages
like trachea, bronchi, bronchioles
Exercises:
__ What are the hair-like structures that move in
a sweeping motion to remove (filter) inhaled
particles along the respiratory tract?
__ What is responsible for mucous secretion to
lubricate and help trap dust and foreign particles
in the respiratory passages?
a. microvilli b. goblet cells c. cilia d. columnar cells
Connective Tissue
• Common features/characteristics of C.T.:
a) Few cells in an extracellular matrix
(solid, semi-solid)
b) vascular
c) matrix contains 3 C.T. fiber types
– Collagen fibers provide strength and
flexibility (strong fibers)
– Elastic fibers stretch and snap back to their
original length (recoil)
– Reticular fibers join connective tissue to
adjacent tissues
• Fibroblast cells- secrete the C.T. matrix
• Functions = mainly binds and supports
other tissues
Fig. 40-5c
Connective Tissue
Loose
connective
tissue
Chondrocytes
Cartilage
Elastic fiber
Chondroitin
sulfate
Nuclei
Fat droplets
Fibrous
connective
tissue
Adipose
tissue
Osteon
150 µm
30 µm
100 µm
120 µm
Collagenous fiber
White blood cells
Central canal
Types of C.T.
1. Loose C.T.
2. Dense C.T.
3. Adipose tissue
4. Cartilage
5. Bone
6. Blood
Blood
55 µm
700 µm
Bone
Plasma
Red blood
cells
Muscle Tissue
• Elongated cells (muscle
fibers) stimulated to
contract; 3 types
1. skeletal muscle –
striated, voluntary muscle;
cylindrical shape
2. cardiac muscle –
striated, involuntary
muscle; cylindricalbranched shape
3. smooth muscle –
nonstriated, involuntary
muscle; spindle or fusiform
shape
Nervous Tissue
• Communication network –
senses stimuli and transmit
nerve signals that help control
body activities
• CNS (brain and spinal cord) and
PNS (nerves and ganglia)
• Consists of neurons (nerve cells)
and neuroglial (supporting) cells
• ___ What is the functional and
structural unit of nervous system?
a. nerve fiber b. neuroglia c. ganglia d. neuron
Integument (Skin)
• 2 main layers- Epidermis and
dermis
• Epidermis- stratified squamous
keratinized; melanocytes protect
from UV radiation
• Dermis- C.T., consists of: a)
papillary layer (loose C.T.), and
b) reticular (dermis proper) layer
(DICT), w/c contain appendages
(hair follicles, sweat glands,
sebaceous (oil) glands, &
arrector pili muscle), blood
vessels, and nerves
• Subcutaneous tissue
(hypodermis) - supporting tissue
w/c binds the skin to underlying
structures (muscles).
Figure 26.5
Homeostasis and Feedback Mechanism
• Homeostasis - Stable internal
conditions regardless of external
conditions= equilibrium
• Negative feedback - Body senses
a change and activates
mechanisms to reverse it (negates
the change); important to maintain
health (good + feedback).
ex: thermoregulation of the body
• Positive feedback - Self-amplifying
change (in the same direction).
ex: fever (bad + feedback); increase
blood clotting to stop bleeding (good +
feedback)
Fig. 40-16
Sweat glands secrete
sweat, which evaporates,
cooling the body.
Body temperature
decreases;
thermostat
shuts off cooling
mechanisms.
Thermostat in hypothalamus
activates cooling mechanisms.
Blood vessels
in skin dilate:
capillaries fill;
heat radiates
from skin.
Increased body
temperature
Homeostasis:
Internal temperature
of 36–38°C
Body temperature
increases; thermostat
shuts off warming
mechanisms.
Decreased body
temperature
Blood vessels in skin
constrict, reducing
heat loss.
Skeletal muscles contract;
shivering generates heat.
Thermostat in
hypothalamus
activates warming
mechanisms.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Homework
Define terms: anatomy, physiology, histology; tissues; organs;
systems; epithelial tissue, connective tissues; muscular tissues;
melanocytes, nervous tissues; homeostasis; negative feedback, and
positive feedback.
Describe characteristics of epithelial tissues as to structural
organization.
Describe simple squamous, simple cuboidal, simple columnar,
stratified squamous, and pseudostratified columnar epithelium as to
cell layer/s and function/s and give an example where these are
located.
Describe the common features of connective tissues, connective tissue
fibers, and types (forms) of connective tissues.
Describe the 3 types of muscle tissues.
Describe nervous tissues.
Discuss the 2 main layers of skin.
What is the importance of hypodermis.
Describe the skin appendages.
Discuss the negative feedback mechanism of thermoregulation by an
example.