This is a draft cheat sheet. It is a work in progress and is not finished yet.
What is Homeostasis?
Dynamic equilibrium that maintains the body’s internal conditions within a stable range around a set point
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Primary Types of Tissue
Type |
Divisions |
Function |
Muscle |
cardiac, smooth, skeletal |
contraction |
Nervous |
central, peripheral |
signaling |
Epithelial |
epithelial sheets, glands |
exchange, division, secretion, absorption |
Connective |
bone, tendons, blood |
anatomical structural support |
Organs are made of a combination of all tissue types
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Cell-Cell Communication
Name |
Type |
Function |
Gap Junctions |
Direct Intercellular Communication |
specialized intercellular connection that directly links the cytoplasm of two adjacent cells, |
Transient Direct Linkup |
Direct Intercellular Communication |
surface molecules of nearby cells join temporarily before breaking away |
Autocrine Secretion |
Direct Intracellular Communication |
cell releases chemical messengers that bind to releasing cell, regulating its own function |
Paracrine Secretion |
Indirect Intercellular Communication |
cell releases chemical messengers that act on nearby cells |
Neurotransmitter Secretion |
Indirect Intercellular Communication |
neuron releases neurotransmitters to communicate with other neurons and target cells |
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Endocrine vs. Nervous Signaling
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Nervous |
Endocrine |
Arrangment |
wired: neurons and their targets are mostly fixed |
wireless: glands and their targets are positioned throughout the body |
Transmission Locaiton |
synaptic cleft |
blood |
Action Distance |
short distance |
long distance |
Speed |
fast |
slow |
The interplay between the endocrine and nervous system is significant to maintaining homeostasis
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Body Systems
Circulatory System |
heart, blood vessels, and blood |
Digestive System |
mouth, esophagus, stomach, intestines, involved organs |
Respiratory System |
lungs and airways |
Urinary System |
kidneys and involved organs |
Skeletal System |
bones and joints |
Immune System |
WBCs and lymphoid organs |
Muscular System |
skeletal muscles |
Integumentary System |
skin |
Nervous System |
brain, spinal cord, nerves, and sense organs |
Endocrine System |
hormone secreting glands |
Reproductive System |
male and female sex organs |
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3 Homeostatic Fluids
Homeostasis involves the exchange of signaling molecules through three main fluids: intracellular
fluid, the interstitial fluid, and blood plasma
Levels of Body System Organization
Atom |
Molecule |
Organelle |
Cell |
Tissue |
Organ |
System |
Organism |
All system layers besides atoms and molecules are dependent on water!
Negative Feedback Example: Temperature
Pathway Segment |
Analogous Physiological Structure/Response |
Stimulus |
body temperature rises |
Sensors |
temperature sensitive cells |
Afferent Pathway |
change in body temperature sent to control center |
Control Center |
thermoregulatory center in brain |
Efferent Pathway |
signal sent to effector organs |
Effectors |
sweat glands |
Response |
body begins to sweat and sweat evaporates |
Result |
body temperature falls |
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Homeostatic Pathway
Sensor: Sensor picks up a deviation from the set point
Afferent Signal: sends information from sensor to Control Center
Control Center: integrates and processes signal
Efferent Signal: sends information from Control Center to Effector
Effector: initiates response to remediate deviation
Response!
Definitions
Term |
Definition |
Dynamic Constancy |
internal body conditions fluctuate about a set point rather than being fixed |
Negative Feedback |
change in a variable triggers a response to oppose the change, bringing system back to set point range |
Positive Feedback |
change in a variable triggers a furthering in response in the same direction away from the set point |
Intrinsic Control Systems |
homeostatic control pathways that are built into an organ itself |
Extrinsic Control Systems |
homeostatic control pathway is maintained outside of the target organ |
Feedforward Mechanism |
homeostatic mechanisms that predicts a change, initiating a response and through body rhythms |
Pathophysiology |
physiological changes in bodily functions due to disease or injury |
Hormone |
signaling molecule secreted by endocrine glands that travel through the blood to reach target organs and cells |
alpha cells |
pancreatic cells that release glucagon |
beta cells |
pancreatic cells that release insulin |
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