Chapter 1: Homeostasis Flashcards
Hierarchy of Cellular Organization
Cells > Tissues > Organs > Organ Systems > Organism
Muscle Cells
specialized to generate mechanical force
What are the three types of muscle cells?
Cardiac, Skeletal, Smooth
Which muscle tissue(s) are involuntary?
Cardiac and Smooth
Which muscle tissue(s) are voluntary?
Skeletal
Neuron
nervous cell specialized to initiate, integrate, and conduct electrical signals to other cells
What does a collection of neruons form?
Nervous tissue
brain or spinal cord
What are the two functions of epithelial cells?
selective secretion and absorption of ions and molecules; protection
Nerve
cellular extensions from many neurons packaged with connective tissue
What is a single-cell-thick tissue of epithelia called?
Simple
What are the four types of epithelial cells?
cuboidal, columnar, squamous, ciliated
What side of the epithelial cell is attached to the basement membrane?
Basolateral side
What is a thick tissue of many layers of epithelium called?
Stratified
What side of the epithelial cell is NOT bound to the basement membrane?
Apical side
What are the two functions of a tight junction in epithelium?
-enables epithelia to form boundaries between body compartments
-selective barriers regulating the exchange of molecules
Connective Tissues
connect, anchor, and support body structures
What are the six types of connective tissue?
loose, dense, blood, bone, cartilage, adipose
What surrounds cells?
Extracellular matrix
What constitutes the extracellular matrix?
proteins, polysaccharides, sometimes minerals
What are the two functions of the ECM?
-scaffolding for cellular attachments
-transmits information
ECM proteins can be
Fibers (collagen or elastin)
Organ
two or more of the four tissue types
Organ system
collection of organs that together perform an overall function
Extracellular fluid
fluid OUTSIDE cells, in the blood
Plasma
fluid portion of the blood
What makes up the majority of the extracellular fluid?
Interstitial fluid
What are the two components of the extracellular fluid?
-plasma
-interstitial fluid
What is the space containing the interstitial fluid called?
Interstitium
Where is intracellular fluid located?
inside of cells
What’s one way cells can regulate their own activity?
maintain differences in fluid composition across cell membrane
Homeostasis
physiological variables in dynamic constancy
What is meant by ‘dynamic constancy’?
Levels change over a short period of time, but remain relatively constant over long periods of time
Pathophysiology
When homeostasis is not maintained
Positive Feedback
Enhances the production of the product or accelerates a process
Negative Feedback
Slows down the production of a product; corrective response
Reflex
an involuntary, “built in” response to a particular stimulus
Reflex Arc
The pathway mediating a reflex
Stimulus
A detectable change in the internal or external environment
Recpetor
Detects the environmental change
Integrating centre
Receives signals and sends them on the AFFERENT pathway
Efferent pathway
Outgoing pathway
Hormone
A chemical messenger secreted into the blood by endocrine cells
Afferent pathway
ingoing pathway
Where do hormones affect?
Cells far away in the body
Neurotransmitters
Chemical messengers released from the endings of neurons onto other neurons, muscle, or gland cells
Where do neurotransmitters affect?
Cells in close proximity
Where do paracrine substances affect?
Cells in close proximity to the site of release
Can neurons and endocrine cells secrete the same chemical messenger?
Yes, but it may function differently
Adaptation
Refers to a characteristic that favours survival in specific environments
Gap junction
Physical linkages connecting cytosol of two cells, allowing molecules to move from one cell to another without entering extracellular fluid
Where do autocrine substances affect?
Acts on the cell from which it was released
Which is reversible: adaptation or acclimatization?
Acclimatization
Juxtacrine signalling
One cell binds to the protein on the surface of another cell
Acclimatization
Improved functioning of an already existing homeostatic system
Circadian rhythm
One 24h cycle
Biological rhythms add what to homeostatic control?
Anticipatory component
Negative balance
loss > gain
Positive balance
gain > loss
Stable balance
gain = loss
Structure indicates _____
Function
What is the most important factor throughout the life cycle?
Homeostasis
