Exam 1 Flashcards
evolutionary thinking of physiology
body’s regulatory mechanisms are a result of millions of years of evolution
what do the systems involved in disease have
ancient origins
what can diseases do in different environments
present differently
conserved
really similar across groups or species
example of conserved
heart in mammals, birds, reptiles are homologous
homology
from common origins
what is the justification for use of mice and rats in medical research
homology
physiology
mechanistic functions of the body, integrated across molecules to the whole organism
what does human physiology link
links the science with dysfunctions, pathologies, and therapies/treatments
what are the different approaches to physiology
mechanistic
teleological
mechanistic approach
seeks to explain HOW events occur
teleological approach
seeks to explain WHY events occur
which approach to physiology is useful for understanding concepts
both
they explain how and why something occurs
example how and why does shivering occur
levels of biological organization
atom molecule organelle cell tissue organ organ system organism
cell
basic unit of living things
basic function of cell
5
energy production, waste elimination, molecule synthesis, transport, reproduction
All functions at the level of cell
tissue
made of many cells plus extracellular material that perform function
organ
a structure made up of multiple tissues that performs function
organ system
collection of different organs performing related functions
organism
a single individual
what is in intracellular (ICF) fluid
large amounts of K+, Mg++, phosphate ions, proteins
what makes up extracellular (ECF) fluid
large amounts of Na+, Cl-, bicarbonate, nutrients (oxygen, glucose, fatty acids), CO2, and other waste products
what happens between ICF and ECF
balance and interaction of ions and nutrients by transport mechanisms
what must be diffused to be balanced for cell function
Mg+ and Na+
Body fluid
what is it made up of
ICF (2/3) ECF (1/3)
Interstitial fluid (3/4 of ECF)
Plasma (1/4) of ECF)
where is interstitial fluid
surrounds cells, tissues, etc.
plasma
liquid portion of blood
homeostasis
body at equilibrium
maintenance of relatively constant internal body conditions- despite changes in external environment through a variety of regulatory mechanisms
what is a central organizing them in biology
homeostasis
what systems are involved with homeostatsis
endocrine and nervous
what happens with the loss of homestasis
body compensates can be successful or fail
parts of the physiological control systems
- stimulus
- sensor
- control center/integrator
- effector
1 - 2 - 3 - 4
4 leads to decrease in 1
1 stimulus
variable shift out of homeostasis
2 sensor (receptor)
structure that detects stimulus
3 control center/integrator
structure that determines set point
set point
normal range of variable
4 effector
structure that generates appropriate response to stimulus in order to return to homeostasis
example of control system
blood pressure
1 stimulus- increase in BP
2 sensor- baro receptors in great arteries of heart detect sensation of stretch
3 control center- brain integrates stimulus and signals for appropriate response
4 effector- heart reduction in HR lowers BP
feedback loops
control systems operate one or more feedbacks loops
can be negative or positive
negative feedback loop
most common
responsible for all physiological regulation
positive feedback loop
continued “vicious” cycle
continues unless ended by major event
example negative feedback loop
calcium levels too low
example positive feedback loop
labor
which feedback loop is rare
positive or negative
positive
negative feedback goal
reduce stimulus to return to homeostasis
positive feedback goal
increase stimulus, continual shift away from homeostasis
allostasis
process of achieving homeostasis through regulatory mechanisms
allostatic load
body “wear and tear” due to allostasis
allostatic overload
cumulative cost of wear and tear
energy demand exceeds supply
what leads to pathologies
allostatic overload
1 nucleus
contains DNA
directing protein synthesis
2 nucelolus
facilitates ribosome synthesis
3 ribosomes (free and attached)
a- ER, free- in cytoplasm
protein synthesis
made up of large (60s) subunit and small (40s) subunit
4 rough ER
protein synthesis
lipid synthesis
protein modification in lumen
5 smooth ER
lipid synthesis
steroid synthesis
assists with packaging and transport
Ca++ storage and release
6 golgi apparatus
process and package products from ER
7 mitochondria
ATP production
comes from cellular respiration
8 lysosome
breakdown old organelles and cellular debris
9 peroxisome
detoxification of wastes, toxins (ex alcohol)
10 plasma membrane
selectively permeable
amphipathic
11 cytoskeleton
structural support
cell movement
cell to cell adhesion
12 cytoplasm
area between plasma membrane and nucleus
which step(s) of cellular respiration happen in cytoplasm
glycolysis
which step(s) of cellular respiration happen in mitochondria
citric acid cycle and oxidative phosphorylation
amphipathic
has hydrophilic and hydrophobic properties
cytosol
liquid surrounding organelles
cell cycles
1 mitosis
2 meiosis
what happens in meosis I
swapping of genetic information
genetically distinct from each other and parent cell
mitosis
1 division
2 daughter cells, genetically identical
somatic cells
2n
meiosis
2 divisions
4 daughter cells, genetically distinct
produces gametes (sperm and egg)
n
DNA structure
sugar (deoxyribose) and phosphate backbone
complimentary nitrogenous bases (linked with hydrogen bonds)
antiparallel strands
double helix
differences between RNA and DNA
RNA is single stranded and has uracil instead of thymine
what does DNA replication produce
identical DNA for cells during S phase
what does it mean when DNA is semiconservative
some of the original is retained
DNA replication steps
enzymes
1 helicase 2 topoisomerase 3 primase 4 DNA polymerase 5 DNA ligase
1 helicase
“unzips” DNA, breaks hydrogen bonds between nitrogenous bases
2 topoisomerase
untwists DNA
3 primase
places primer
primer
short sequence of RNA that marks starting point of replication
4 DNA polymerase
produces new complimentary DNA 5’ to 3’
leading strand
goes 5’ to 3’
lagging strand
okazaki fragments
backwards 3’ to 5’ so has to work backwards creating these fragments
5 DNA ligase
seal gaps between okazaki fragments
complimentary DNA nitrogenous bases
C to G
A to T
central dogma of molecular biology
DNA replication to transcription to RNA to translation to proteins
replication bubble
an unwound and open region of a DNA helix where DNA replication occurs
transcription
DNA to RNA
produces mRNA, copying portion (gene)
mRNA is complimentary, have all info needed
copying of information
promoter
starting point of transcription of DNA to RNA
terminator
end point of transcription of DNA to RNA
how transcription works
1 protein factors bind to DNA at promoter
2 recruitment of RNA polymerase II binding to promoter
3 transcription of gene
mRNA processing
1 Introns removed, exons spliced
2 3’ Poly- A tail added
3 5’ methyl-guanosine gap added
intron
non coding region of RNA
why do we add a 3’ poly- A tail and 5’ methyl-guanosine gap
help to stabilize mRNA
translation
conversion of mRNA to amino acid chain
where does post translational modification of mRNA happen
in RER
where is the protein packaged
in golgi apparatus
how many gene’s affect individual physiology
many genes
how does genotype and environment interact
variation in physiological responses
what can diffuse through membrane
small, non polar substances
what cannot diffuse through membrane
large, polar, or charged molecules,
how do molecules get through the membrane if they cannot diffuse
by a protein channel
example of molecules that can diffuse
lipids/steroids, O2, CO2, alcohol
examples of molecules that cannot diffuse
glucose, amino acids, ions
modes of transport
simple diffusion
facilitated diffusion
osmosis
active transport
simple diffusion
substances move from area of high concentration to area of low concentration, until equal
concentration gradient
area of a lot to area of a little
facilitated diffusion
substances diffuse from high concentration to low concentration with help of integral protein channel
what is osmosis specific to
water
osmosis
water moves to areas with high concentration of solutes
what is required for active transport
ATP
active transport
how do substances move in regards to concentration gradient
substances move against concentration gradient
secondary active transport
what does it rely on
movement relies on gradient established from primary active transport
what is the primary active transprot
NA+/K+ pump
how does the Na+/K+ pump work
- intracellular 3 Na+ ions bind to pump
- ATP is hydrolyzed to ADP + P, P binds to pump
- this provides energy to change configuration of the pump, expelling Na+ to the outside
- two extracellular K+ ions bind to the pump, phosphate group on the pump get released
- pump changes back to its original configuration
- K+ is released inside the cell and the cycle repeats
what does the concentration gradient created by Na+/K+ pump do
what does it power?
what is it important for
helps maintain resting membrane potential
powers secondary active transport
important for neurons and muscle fiber function
what is resting membrane potential
relative difference in charge across plasma membrane
ATP as an energy source
energy stored in bonds between phosphate groups
what happens during hydrolysis to ATP
ATP to ADP+P which releases energy for use
secondary active transport
name a secondary active transport
SGLT
sodium glucose transporter
SGLT
how does the SGLT work
set up by Na+/K+ concentration gradient
uses downhill Na+ gradient to move glucose against concentration
Na+ and glucose enter together
what does cell communication rely on
what is cell communication used for
chemical signals for cells to communicate
chemical bioregulation to help maintain homeostasis
what 3 systems work together for cell communication
immune, nervous, and endocrine
all interact
5 categories of chemical messengers/signaling
1 intracrine 2 autocrine 3 paracrine 4 endocrine 5 exocrine
1 intracrine communication
chemical signal produced in the cell and it regulates intracellular activity of that cell
2 autocrine communication
chemical signal produced in the cell, signal binds to receptor on the membrane of that cell
3 paracrine communication
chemical signal that affects an adjacent cell
where is paracrine communication commonly seen
with neurons
4 endocrine communication
chemical signal (hormone) that enters the bloodstream and travels to “distant” target cell within the body
5 exocrine communication
chemical signal that leave the body and is detected by a different individual
example of exocrine communication
pheromone
what kind of signal communication is neurotransmitter
paracrine
what kind of signal communication is neuromodulator
paracrine
what kind of signal communication is neurohormone
endocrine
chemical messenger
any substance produced by a cell that affects the function of the cell
cytokine
chemical messenger that evokes proliferation of other cells, especially in the immune system
hormone
a chemical messenger that is released into the bloodstream that affects the function of a target cells some distance from the source
neurotransmitter
a chemical messenger secreted by a neuron into the synaptic space
neuromodulator
a chemical messenger secreted by a neuron into the synaptic space and adjusts the sensitivity of target to other neurotransmitters
neurohormone
a hormone produced by a neuron, travels through bloodstream
long distance communication
what systems help accomplish
what must target have
accomplished by nervous and endocrine systems
target must have receptor for chemical signal
where are cell connections present
at lateral or basilar sufaces
desmosomes
bind cells together
tight junctions
forms “tight seal”, creates permeability barrier
what does cell connection do
can enhance their communication
gap junction
channel allowing cell communication via ions
intercalated disk
projections that hold cells together
receptors
what is it
what does it bind
what does it produce
protein molecules located on cell surface or interior
bind specific ligands in specific target tissues
produce a biological effect
how do signal molecules work
signal molecule BINDS TO receptor protein ACTIVATES intracellular signal molecules ALTER target proteins CREATE response
ligand
any chemical signal
properties of receptors
the most important factor for a cell responding to a ligand is if it has appropriate receptors to which ligand can bind
specificity
affinity
receptors undergo a conformational change when bound by a ligand
what happens if a cell doesn’t have a receptor for a ligand
if it does not have receptors for that ligand, no effect will occur
where can receptors be
intracellular
or
on the cell membrane
where are receptors found if the are intracellular
in cytosol or nucleus
specificity
receptors distinguish their ligands from others
affinity
strength of binding, how much wants to bind
conformational change
can change shape, structure
what happens when a ligand is bound
what is activated
activation of biochemical pathways within the cell
conformational change
cells response to being bound occurs via
via modified protiens
what does a modified protein alter activity of
1 metabolic enzymes
2 motor proteins for muscle contraction or cytoskeletal movement
3 proteins that regulate gene activity
4 membrane transport and receptor proteins
signal transduction
how it works
1 extracellular signal ligand activates a receptor
2 transmission of signal to the intracellular environment via biochemical activity to produce a cellular response
what happens to the signal during signal transduction
signal is transduced and amplified
where are ion channels located
in plasma membrane
types of ion channels
voltage- gated ion channel
ligand- gated ion channel
voltage gated ion channel
opens or closes in response to a change in cellular charge
ligand gated ion channel
open or close in response to presence or absence of a chemical signal
explain how ion gated channel works
ligand gated
1 gate closed, inactive, no ligand bound and gate closed
2 ligand will bind to the receptor portion
3 active state, ligand bound gate opens, allows ions to enter, leads to a response in the cell
3 to 1 ligand dissociates/ unbinds from receptor
1 to 2 to 3 to 1
intracellular receptors
how it works
signaling molecule has to diffuse through and then bind to its receptor
whole complex travels to nucleus
bind to the DNA and
acts like a transcription factors
hormone
chemical substance produced in a specialized gland (endocrine gland) released into bloodstream transported to (sometimes) distant target cells/tissues to elicit a response
hormone pathways and interactions
physiological control system
stimulus, multiple control systems, response in target tissue
general features of the endocrine system
glands
hormones can be up regulated or down regualted
development of glands
what kind of glands are developed
endocrine and exocrine glands
where are glands derived from
epithelium
what are exocrine glands
hollow center with duct
what are endocrine glands
ductless- no link to parent epithelium
highly vascularized
hormone binding basics
what does hormone interact with
interact with cell with appropriate receptor
hormone receptors
what are they specific to
usually specific to a single hormones or hormone classes
example of hormone receptor specificity
T and DHT bind to androgen receptor
estrogen receptor have alpha, beta, and gamma
up regulation
cell makes more of a certain receptor, makes cell more sensitive to hormone
down regulation
cell reduces a certain receptor, makes cell less sensitive to hormone
3 major classes of hormones
based on structure
steroid hormones
peptide hormones
amine hormones
steroid hormones
derived from
derived from cholesterol, lipid based,
example of steroid hormones
testosterone (T)
estradiol (E2)
cortisol
peptide hormones
made of
chains of amino acids
example of peptide hormones
many
insulin
growth hormone
gonadotropin releasing hormone (GnRH)
Amine hormones
derived from
derived from a single specific amino acids
what amino acids can amine hormones be produced from
tyrosine
tryptophan
example of amine hormones
thyroid hormones
monoamines
serotonin
epinephrine
peptide hormone synthesis
made in advance, stored in secretory vesicles
peptide hormone receptor location
cell membrane
steroid hormone synthesis
synthesized on demand from precursors
steroid hormone receptor location
cytoplasm or nucleus; some have membrane receptors also
amine hormone synthesis
made in advance, stored in secretory vesicles,
amine hormone receptor location
cell membrane or nucleus
types of cell connections
desmosomes
tight junctions
gap junctions
intercalated disks
what are hormone classes based on
structure
1 cell membrane
hormone receptor location
response
fast response (seconds to minutes)
what hormones has receptors on the cell membrane
peptides and most amine
2 intracellular
hormone receptor location
response
slower response (20-90 minutes)
what hormones have receptors intraclelular
steroid and thyroid hormones
g protein coupled receptors
cross plasma membrane 7 times, has 3 protein subunits and a GDP molecule bound to the alpha subunit
what are the 3 protein subunits on a g protein coupled receptor
alpha, beta, gamma
what is bound to a protein subunit alpha on an inactive protein coupled receptor
molecule GDP
what is a g protien
alpha, beta, gamma protein subunits and bound GDP to alpha subunit
what happens when a g protein coupled receptor is bound by a ligand
conformational change
what happens when a ligand leaves a g protein coupled receptor
goes back to resting state, inactive
what other molecules are present in the g protein coupled receptor process
1 adenylyl cyclase
2 cAMP (cyclic AMP)
3 protein kinase A
2nd messenger
intracrine communication
adenylyl cyclase
amplifier enzyme
cAMP
produced from ATP, 2nd messenger
protein kinase A
type of kinase
phosphorylates protein
steps of G protein coupled receptor signal transduction pathway
1 ligand binds to receptor
2 GTP replaces GDP on alpha subunit, alpha subunit dissociates
3 alpha subunit activates adenylyl cyclase
4 adenylyl cyclase produces cAMP from ATP
5 cAMP activates protein kinase A
6 protein kinase A phosphorylates intracellular proteins
7 response in the cell
example of cell membrane receptor
g protein coupled receptor
does a ligand for an intracellular receptor have to enter the cell
yes
what does the activated steroid receptor do
initiates transcription
what do you get from an activated steroid receptor
production of new proteins
response in cell
is the relationship between hypothalamus and pituitary important
yes
what does the relationship between the hypothalamus and pituitary form
regulatory complex
serve as regulatory system for many functions
how does the hypothalamus and pituitary regulatory system work
1 hypothalamus secretes neurohormone
2 neurohormone travels to anterior lobe of pituitary
3 pituitary secretes hormones in response
4 hormones travel to other endocrine structures or target tissues to produce a response
what percentage of the pancreas is endocrine cells
2%
where are the endocrine cells in the pancreas found
islets of Langerhans
what type of cells are in the islets of Langerhans
Beta cells
Alpha cells
D cells
F cells
what percentage of Beta cells are in the Islets of Langerhans
75%
what does beta cells produce
insulin
what percentage of Alpha cells are in the Islets of Langerhans
20
what does alpha cells produce
glucagon
what percentage of D cells are in the Islets of Langerhans
4
what does D cells produce
somatostatin
what percentage of F cells are in the Islets of Langerhans
1
what does F cells produce
pancreatic polypeptide
why is insulin unique
only hormone to reduce blood glucose
pancreas in terms of endocrine function
glucose homeostasis
what happens if glucose is high
insulin released, induces target cells to take up glucose
blood glucose levels go down as a result
what does glucose do
major source of energy
breakdown for ATP
is glucose important for cellular function
yes
what happens if glucose is low
glucagon is released, induces release of glucose from target cells
blood glucose levels go up as a result
what produces insulin
beta cells in islets of Langerhans
what is insulin needed for
normal growth and development
what is the only hormone that lowers blood glucose
insulin
what type of hormone is insulin
peptide hormone
what is the stimulus for secretion of insulin
increased glucose in blood
what target tissues does insulin act on
liver, muscle, and adipose tissue
what type of muscle does insulin affect
skeletal
what does the the enhanced uptake of glucose by cells do
lowers blood glucose levels
what can skeletal muscle do during exercise
pull in glucose
what does insulin do at its target tissues
enhances uptake of glucose by cells
what does insulin do
initiates what
initiate facilitated diffusion through glucose transport protein (GLUTs)
what happens if insulin is absent
unregulated glucose levels
hyperglycemia
can cause neural shock
diabetes mellitus
type 1
type 2
gestational diabetes
type 1 diabetes
autoimmune destruction of beta cells, no insulin production
type 2 diabetes
receptors for insulin are non-functional (insulin resistance)
initial upregulation of insulin secretion followed by reduction of insulin secretion
which type of diabetes has a strong genetic disposition
type 2
gestational diabetes
insulin resistance or reduction of insulin during pregnancy
where is glucagon produced
alpha cells
what is the target tissues of glucagon
liver and adipose tissue
what does glucagon do
induces glycogenolysis, gluconeogenesis, and lipolysis
increases blood glucose
what is glucagon to insulin
antagonistic
opposite action to insulin
glycogenolysis
breakdown of glycogen into glucose,
lysis
breakdown
gluconeogenesis
producing glucose
lipolysis
breakdown of fats
