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Homeostasis:
The process of mantaining a relatively stable internal environment
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Negative feedback:
Reverses a change in a controlled condition
the resopnse is directly opposite the inital stimulus.
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Positive Feedback systems:
Strengthen or reinforce a change in one of the bodys controlled conditions
response is in the same direction as the initial stimulus.
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Feedforward Mechanisim:
-learned resopnse, can be unlearned
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Control Mechanisms/intrinsic control:
when the control comes from "within" the organ
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Control Mechanisms/extrensic control
when the control comes from outside the organ of action-
typically from the nervous or endocrine system eg. "thinking abut food"stimulates an increase in stomach muscle contractions
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epithelial membranes:
a combination of an epithlial layer and an underlying connective tissue layer
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Mucous Membrane (mucosa):
- Areolar CT = Lamina propria
- epithelium varies; tight junctions, goblet cells (mucin)
- eg, respiratory, digestive, reproductive, most of urinary systems
- always wet
- open to exterior
- important for the body's defense against pathogens
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Serous Membrane (serosa):
- Areolar CT + Mesothelium (simple spuamous epithelium)
- double layered; visceral & Parietal layers w/serous fluid
- eg, pleura, pericardium, peritoneum
- lines body cavity that does not open directly to the exterior
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Cardiovascular system =:
- Heart
- Blood Vessels
- Blood (connective tissue); (RBC's & WBC's, platelets, proteins)
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Blood Flow=:
- Heart
- arteries
- arterioles
- capillaries
- venules
- veins
- heart
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Systemic Circulation:
to and from the body
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Pulmonary Circulation
to and from the lungs
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Heart is composed of 3 layers:
- endocardium
- myocaardium
- epicardium
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The perecardium is composed of 3 layers
- fibrous pericardium
- parietal layer of the serous pericardium
- visceral layer of the serous pericardium
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endocardium:
internal lining (of the heart) of mucous membrane with endothelial cells (simple squamous epithelium, the endothelium)
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Myocardium:
the middle layer, of the heart, walls of cardiac muscle with dense irregular connective tissue borders & fetures
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Epicardium:
acts as the external "skin" of the heart, also cts as the visceral lyer of the serous pericardium
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Fibrous pericardium
an outer tough dense irregular connective tissue conering, surrounding the serous membrane
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Parietal layer of the serous pericardium
areolar connective tissue in contact with the fibrous pericardium, lined with mesothelium, secreting serous fluid
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viscerl layer of the serous pericardium
areolar connective tissuein contact with the heart's myocardium, lined with mesothelium, secreting serous fluid, also acts as the hearts epicardium
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*** INTERCALATED DISCS***:
on test
***Desmosomes & Gap Junctions***
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***DESMOSOMES***
CONTAIN PLAQUE AND CADHERINS THAT EXTENDS INTO THE INTERCELLULAR SPACE TO ATTACH ADJACENT CELLS TOGETHER
STRENGTH WITH "STRETCH" (LIKE VELCRO)
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***GAP JUNCTIONS***
- CONNECT NEIGHBORING CELLS VIA TINY FLUID FILLED TUNNELS CALLED CONNEXONS
- COMMUNICATION OF CELLS WITHIN A TISSUE
- IONS NUTRIENTS WASTE CHEMICAL AND ELECTRICAL SIGNALS TRAVEL THROUGH THE CONNEXONS FROM ONE CELL TO ANOTHER
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Skeletal Muscle Tissue
- Attached to bones of the skeleton by tendons
- have striations
- voluntary-movement or contractions by conscious control
- Ca++ stored in large complex sarcoplasmic reticulum
- neurogenic- somatic nervous system
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Smooth Muscle Tissue
- walls of hollow internal structures (single Unit)
- -blood vessels, airways of lungs, stomach and intestines
- Nonstriated
- usually invoulantary control
- myogenic - with autonomic nervous system innervation
- Ca++ from ECF
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Cardiac Muscle Tissue
- Have striations
- Involuntary movement or contraction is not consciously controlled
- intercalated disc unique to cardias muscle tissue w/high densities of desmosomes & gap junctions
- myogenic w/ autonomic nervous system innervation
- Ca++ from ECF and sarcoplasmic reticulum
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Autorhythmic fibers (1%) = pacemaker cells
- Conduction system
- -sinoatrial (SA) node
- -Atrioventricular (AV) node
- -Atrioventricular (AV) bundle (Bundle of His)
- -w/ right and left bundle branches
- -Purkinje fibers
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Contractile fibers (99%)
- the workhorse cells-no pacemaker potential
- action potential with plateau due to membrane Ca++&K+ channels opening at the same time
- depolarization lasts approximately as long as contraction
- refractory period basically negates possibility for summation
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Electrocardiogram (ECG)
- record of electrical changes
- -P wave
- -QRS wave
- -T wave
- -P-Q interval, S-T segment, Q-T interval
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***P wave***
ATRIAL DEPOLARIZATION
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*** QRS complex***
- VENTRICULAR DEPOLARIZATION
- covers atrial repolarization-can be uncovered
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***T-wave***
VENTRICULAR REPOLARIZATION
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P-Q interval
time between start of atrial and ventricular excitation (depolarization)
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S-T segment
the time of ventricular depolarization
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Q-T interval
from the beginning fo ventricular depolarization to the end of ventricular repolarization
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End diastolic volume (EDV)
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End systolic volume (ESV)
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Stroke Volume (SV)
SV= EDV - ESV
-
isovolumetric contraction
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Heart sounds
"heart beat"- Lubb & Dupp
- Heart murmurs
- -stenotic valves or incompetant valves
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