Lecture 2: Homeostasis (and Cells) Flashcards
what is homeostasis?
homeo-sameness
stasis-standing
is the body remaining a relatively constant internal environment by the function of cells, tissues and organs, despite a constantly changing external and internal environment
why is homeostasis important?
-maintains life of the body
-important in understanding both normal function and certain disabilities and disease
-core concept of physiology
homeostasis is a constant process of cause and effect, it is not true that……but rather
it is not true that the body wants what is best for itself,, it is true that homeostatic regulation occurs regardless of what may be best
what is an example of how homeostatic regulation occurs regardless of what is best?
blood pressure regulation and hemmorhage
-major blood loss –> decreased bp –> bp regulated by homeostasis –> faster blood loss
there are homeostatic regulated variables called…
the big 10
dont need to memorize but a lot to do with blood
it is not true that non-homeostatic regulated variables aren’t important, but rather…
other variables have their own functions and help support homeostasis
how does the body regulate the big 10?
- via the nervous system and/or endocrine system
- through a process called a feedback loop
what are the different parts of the feedback loop in order?
- stimulus (anything that causes change)
- controlled variable/system (one of the big 10)
- sensor (type of receptor)
4a. integrator (brain or endocrine organ)
4b. set point - effectors (cell, tissue, organ)
- response (physiological change)
know the feedback loop like the back of your hand
;)
what are the two types of feedback loops?
- positive feedback
- negative feedback
what is a positive feedback loop?
when the response is in the same direction as the stimulus
pro change
ex. childbirth and contractions,, baby begins to come out, so the body pushes harder to get it out
what is a negative feedback loop?
when the response is in the opposite direction of the stimulis
homeostasis uses_______ feedback loops only
negative
look at the cruise control as a negative feedback example
;)
homeostatic feedback is like a ________ not a _________
volume knob
light switch
go look at the blood osmo. and blood glucose feedback examples
;)
the cytoplasm
a combination of the cytosol and the organelles
what is the cytosol?
a jelly like substance that provides a fluid like medium for chemical reactions within the cytoplasm
what are organelles?
tiny organs
what is the nucleus?
-the central organelle
-contains DNA
-contains nucleolus
-contains chromatin
what is the nucleolus?
a structure within the nucleus with specific functions
what is the chromatin?
a complex combination of DNA and protein
endoplasmic reticulum?
a system of passages with the nucleus that allow for synthesis transport, and storage of cellular materials
2 forms (rough and smooth)
rough ER
-ER covered in ribosomes giving it a rough appearance
-important in protein synthesis
smooth ER
-involved in lipid synthesis and detoxification of foreign substances (drugs)
golgi apparatus
the “post-office” of the cell
-sorts, modifies, and transports products from the rough and smooth ER’s
-products are transported through Golgi vesicles
vesicles
-liquid or cytoplasm enclosed by a phospholipid bylayer used for transport purposes
vesicular transport is used when…
- large substances need to be moved across the plasma membrane
- large quantities of substances need to be moved quickly
what are the two types of vesicular transport?
- exocytosis: moves substances OUT of the cell
- endocytosis: brings substances INTO the cell
what are the lysosomes
-the “garbage trucks” of the cell
-contain hydrolytic enzymes
-also break down old cellular structures and foreign substances, and can cause the cell to self destruct if needed
-generated by the golgi
mitochondria
-plural-mitochondrion
-synthesizes ATP through cellular respiration and is the site of major metabolic reactions
-some cells have more ATP than others
why would some cells have more ATP than others?
some cell types need to process more energy than others ie. muscle cells
what are peroxisomes?
-similar to lysosomes but contain digestive enzymes
-have some metabolic functions, make lipids and cholesterol
the cytoskeleton
-groups of proteins that provide structural support for the cell
-supports cell motility, cell reproduction, and transportation of substances within the cell
-microtubules, microfilaments (actin) and centrosomes
