histology the study of tissues. homeostasis maintenance of a constant internal environment. we...
TRANSCRIPT
HistologyThe study of tissues
Homeostasis
• Maintenance of a constant internal environment.
• We Don’t Like Stress.
• Physiology identifies and studies the mechanisms of homeostasis.
• Controlled by Two Systems– A.– B.
Levels of Organization
Cells
Tissues
organs
organ system
organism
Tissuesgroups of cells with a common structure and function
Four categories
epithelial
connective
muscle
nervous
Epithelial tissuelocation: outside of body, line organs and cavities
Function: barrier, absorption or secretion– Glandular secretory portion of gland
2 types
simple - one layer
stratified - multiple layers
“pseudostratified” appears stratified due to cells of various lengths
Epithelial tissueCell Shapes
squamous - floor tiles
cuboidal - dice
columnar - bricks on end
Simple SquamousLeaky to allow diffusion/osmosis.
Capillaries, alveoli.
May be keratinized on body surfaces.
Connective Tissue
Basement Membrane
Stratified Squamous
Connective Tissue
Readily sloughed off.
Skin, anus, vagina.
Simple Cuboidal
Area of secretion or absorption.
Stratified Cubiodal
Simple Columnar
Ciliated Columnar
Lumen of vessel
High secretion and absorption, High SA/VOL
Pseudostratified ColumnarPseudostratified Ciliated Columnar
Some cells do not reach the surface
Connective TissueMOST ABUNDANT TYPE OF TISSUE.
binds and supports other tissues, TRANSPORT, FRAMEWORK, STORE ENERGY
cells create a matrix/ web of fibers [Matrix non-living web of fibers.]
3 kinds of fibers
collagenous fiber - made of collagen
Elastic fibers - Elastin Protein
reticular fibers - Thin collagen fibers
Types connective tissueloose connective binds epithelia to underlying tissue; holds organs
1-Fibroblasts- secretes extracellular proteins
2-Macrophages- amoeboid WBC’s; phagocytosis
3-Adipose tissue- fat storage; insulation
Types of Connective Tissuefibrous connective - parallel Bundles of cells
Ligaments, Tendons,
cartilage - collagen in rubbery matrix
bone - mineralized tissue
blood - liquid plasma matrix
Collagen
Tough, somewhat flexible protein. Provides the toughness of meats.
Very strong, resists longitudinal stress (tensile strength). Underlies epithelial tissue.
Elastic fibersLong threads of elastin.
Easily returns to original shape (rubberband). This is from an aorta. Also found in skin and lungs.
Small, unbranched.
Secreted by fibroblasts.
Nuclei of Fibroblast
Loose Connective Tissue (areolar)
• Loose web of fibers (all 3)
• Fills space between organs (Styrofoam peanuts). Gel-like matrix.
• Composed of elastin (elasticity), collagen (strength), reticular fibers (support/form).
• Edema: excess interstitial fluid absorbed by LCT
Dense Connective tissue
Tendon Fibrous Connective Tissue.
Bundles of collagenous fibers. Secreted by fibroblasts.
Non-elastic. Resists pulling forces
Fxn: strong attachment between structures (tendons & ligaments)
Nuclei of Fibroblast
CartilageHyaline
Elastic cartilage
Chondrocyte
Large amount of collagen, embedded in chondroitin sulfate.
Provide rigid support. Nose, ear, trachea, interverterbral disks.
Reduces friction on ends of long bones, absorbs shock
Blood
Eosinophil
Neutrophil
Connective tissue with liquid matrix (plasma). Two types of cells RBC’s (Erythrocytes) and WBC’s (Leukocytes)
Plasma composed of H2O, NaCl, plasma proteins
R.B.C’s
W.B.C.
Adipose (FAT)
Nucleus
Adipocyte
15% Male body wt.
22% Female body wt.
Bone
Osteocytes
Haversian System/ Canal
Support, protection, storage, movement.
Osteocytes produce collagen + calcium phosphate hydroxyapatite
Muscle Tissuelong cells called muscle fibers capable of contracting when stimulated
3 types
Smooth - involuntary
Skeletal - voluntary
cardiac - walls of heart
MuscleSkeletal Muscle Cardiac Muscle
Fxn: Motion, Heat production, maintain posture.
Highly specialized for contraction
Aka. VoluntaryStriated, branched.
Intercalated disks to speed impulse.
Smooth Muscleaka: visceral, unstriated.
Surround hollow structures (stomach, blood vessels, intestine, bladder.
Nervous tissue
neuron or nerve cell
specialized to transmit nerve impulses
Dendrites: transmit impulses from tips to rest of neuron
Axons: transmit impulses toward another neuron or effector
Neuron and Glial Cells
Nervous Tissue
Neuromuscular Junction
Create a presentation: use microscope pictures
Show the All types of epithelial: simple squamous, simple cuboidal, stratified squamous, simple columnar
tell what they are where they would be located
SHow types of connective tissue and what they do:
adipose, cartilage, loose connective, ground bone (no longer a ground bone slide)
show the 3 kinds of muscle tissue and how to tell them apart:
Skeletal, cardiac, smooth
Show a neuron - what are the axons and dendrites? - Use a web picture
Organ systems
Organ: organization of tissues
Mesentaries: suspension of organs (connective tissue)
Thoracic cavity (lungs and heart)
Abdominal cavity (intestines)
Diaphragm (respiration)
Organ systems…...
Digestive-food processing
Circulatory-internal distribution
Respiratory-gas exchange
Immune/Lymphatic-defense
Excretory-waste disposal; osmoregulation
Endocrine-coordination of body activities
Reproductive-reproduction
Nervous-detection of stimuli
Integumentary-protection
Skeletal-support; protection
Muscular-movement; locomotion
Regulation of Internal Environment
Interstitial fluid: internal environment of vertebrates; exchanges nutrients and wastes
Homeostasis: “steady state” or internal balance
Negative feedback: change in a physiological variable that is being monitored
response counteracts the initial fluctuation;
i.e., body temperature
i.e., uterine contractions at childbirth
Positive Feedback
Positive feedback: physiological control mechanism in which a change triggers mechanisms that amplify the change;
Metabolism: sum of all energy-requiring biochemical reactions
Size vs. Metabolic Rate
Inverse relationship
Small = high metabolic rate
Large = low metabolic rate
Endotherms: bodies warmed by metabolic heat
Ectotherms: bodies warmed by environment
Basal Metabolic Rate (BMR): minimal rate powering basic functions of life (endotherms)
Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)
Countercurrent exchange
Counter Current -Common process in multiple systems
Heat exchange example