Homeostasis and Cell Biology
Components of a feedback system
1. Receptor to detect stimulus 2. Integrating center- assess input and initiate response 3.Effector- generates response to change internal enviroment
describe the levels of cellular organization and the four types of specialized cells and tissues.
1. cells divide and differentiate into four specilaized types- muscles, neruons, epithelila, and connective tissue 2. tissues- muscle, nervous, epithelial, connective. Tissues arise from the aggregation of similar cells 3. different tissues form an organ 4.organ system consits of a group of organs that perform a specific function
identify the classes of organic molecules in the plasma membrane
1. lipids- phospholipids, cholesterol 2.proteins- receptors 3.carbohydrates- glycoproteins and glycolipids
golgi apparatus function
1. modifies the proteins it receives from rough ER through adding on a carbohydrogen, shortening the protein 2. sorts and packages into cesicles 3. delivered to specific orgnalles or the plasma membrane for secretion
classification of cells
1. number of layers- simple, stratified, psudostratified 2. cell shape- columnar, cuboidal, squamous
golgi apparatus
1. processes (glycosylation in which it adds a carbohydration) 2. packages proteins into vesciels 3. distributes pacakaged protein and lipids within and out of the cell. Endocrine cells have an extensive golgi appartus.
components of feedback system
1. receptor 2. integrating center 3. effector
purpose of cell membrane
1. selective barrier 2. detects chemical signals 3. anchor cells to adjacent structures
cellular functions
1. transport 2. protection 3. production of ATP 4. excretion of wastes 5. movement 6. reproduction 7. secretion of hormones
typical cell composition
1. water 70-85% 2.Proteins 10-20% 3.Lipids 4.carbohydrates 5. ions
negative feedback vs. feedfoward
A negative feedback system generates a response that looks to generate a response opposite of the initial stimulus to restore the variable towards its original set point. A feedfoward regulation occurs before homeostasis has been interrupted and helps to minimize fluctuations and speed up the response. A feedfoward regulation initiates an adaptive response in the body in anticipation of a change in the environment- production of saliva and release of enzymes enzymes, increase in HR before a race
acclimation vs adaptation
Acclimation is an improved ability to respond to environmental stress due to prolonged exposure. This is not inheritable. This is improved functioning of an already inherited homeostatic system. Adaptation- change in structure and function of a cell or organ system that results in improved ability to maintain homeostasis
State the four specialized cells and tissues found in the body
Cells differentiate into four types- muscles, neurons, epithelial, and connective tissue. This give rises to epithelial tissue, nervous tissue, connective tissue and epithelial tissue. Similar cells aggregate to form tissue. Organs are combination of different tissue types.
feedfoward vs negative feedback
Feedfoward regulation is an adaptive response that is learned and anticipates a change in the environment. Feedfoward regulation happens before homeostasis has been disrupted to help minimize fluctuations and speed up the reaction. negative feedback occurs only after there has been a change in the enviroment and looks to restore the variable at its original set point. The response is opposite to the stimulys
relative volume of water in the body fluid compositions
ICF is twice as large 67%, ECF 33% ICF-28 L ECF-14L
ECF? What it is composed of
Interstitial flyis and blood plasama, account for one third of total body fluid The intersitial fluid 11L (75-85% of ECF) The plasma 3L (20-25% of ECF) except for protein concentration and RBC in plama they are identical
Relative volume of water in the body fluid compartments
Intracellular fluid- 28 L makes up 66% of total body fluid Extracellular fluid (11 L interstitial and 3 L plasma) makes up 33% of total body fluid
explain the function and location of epithelial tissues
Location: epithelial tissue covers the body's surfaces and lines the body cavities. Function: protective barrier, performs secretion, absorption, excretion, filtration
Do men or women have a higher water content?
Men due to more lean muscles
What two fluids make up the extracellular fluid, what are their relative proportions and how do they differ?
Plasma-3 L (25-20% of ECF) Interstitial fluid-11 L (75-80% of ECF) ECF makes up 1/3 of total body fluid They are similar in composition minus difference in protein concentration and RBC in plasma
Rough ER vs. Smooth Er
Rough Er consists of a network of membranes that enclose an extensive space in the cell, flattened sacs studded with ribosomes, packages and synthesizes PROTEINS TO BE SENT TO THE GOLGI!! Smooth ER is more tubular and branched, synthesizes lipids and hormones, STORES CALCIUM, detoxification
how does regular bouts of exercise improve homeostatic control?
acclamation is the improved homoestatic control due to prolonged exposure ro enviromental stresses. Body gets better at responding to heat. Acclimization is not inherited. Adaptation- change in cell or organ structure/ function that improves ability to maintain homeostasis
where might simple squamous epithelial cells be found
alveoli/ blood vessels
feedfoward regulation
anticipatory event utilizes external/internal enviormental detectors to prepare the body before homeostasis is disrupted learned over time
positive feedback
causes further enhancement of the response bought on by the stimulus. Baby's head pushes against cervix (stimulus) causes release in oxytocin, response- muscle contraction, body releases more oxytocin
cell theory
cell is the basic unit of life all living things are made up of one or more cell new cells arise from preexisting cells
lysosomes
contain hydrolotic enzymes, autdigestion and apoptosis, fuse with phagosome- vacuole with phagocytosed particles
peroxisomes
contain oxidative enzymes to neutralize free radicals
cytoplasm vs cytosol vs intracellular fluid
cytoplasm- cellular organelles, fluid they contain, cytosol, excludes nucleus cytosol - fluid within a cell but outside of the organelles intracellular fluid- cytosol, fluid within organelles, and fluid within the nucleus
fibrous connective tissue
dense- tendons and ligaments loose- ECM
Why are there more proteins than genes?
different MRNA sequences can arise from the same DNA gene based off how the exons are spliced together
gap junctions
electrical activity, protein channels link the cytosol, connexon proteins
role of glycolipids
found on extracellular surface of the cell intercellular communication
explain what connective tissue's function is and how it is classifed
function- binds and supports the body 1. Fibrous connective tissue (dense and loose) 2. Supportive connective tissue (bone cartilage) 3. Fluid connective tissue (blood and lymph)
tight junction
holds together two cells so there is no extracellular space between them epithelial cells are joined by tight junction that line the lumen of nephron so that some molecules are impermeable
positive feedback
looks to further amplify the stimulus
extracellular matrix function
mechanical support for cells and tissues, influences cell shapes, role in cell signaling
muscle tissue
moves the body
peroxisomes
organelle that contains oxidative enzymes to neutralize free radicals
classes of organic molecules found in the plasma membrane
phospholipid bilayer, cholesterol which is a steroid that maintains the integrity when faced with changes in temperature, protein receptors are on the plasma membrane or in the nucleus/cytosol. Glycolipids and glycoproteins for cellular communication/immune system in which carbohydrates are attached to lipids and proteins.
mitochondria
power house of cell size, shape, and number varies depending on cell type self replication regulate apoptosis generate ROS maternal mitochondrial DNA linked to neurodegenerative diseases
prokaryotic v eukarytoic
pro= lacks membrane bound organelles and a nucleus
nervous tissue
receives stimuli and conducts nerve impulses
rough ER vs. Smooth ER
rough er- flattened cisternae studded with ribosomes, membranes enclose extensive space within the cell, responscible for protein synthesis and packaging where it is sent to the Golgi apparatus. smooth er- way more tubular and no ribosomes! site of lipid and steroid synthesis, detoxification, stores intracellular CA
desmosomes
skin/bladder, dense plaques, holds together firmly
homeostasis
systems that maintain dynamic physiological constancy. Maintains internal stability in response to stimuli that disturb normal functioning
differentiation
the process through which cells become specialized to carry out certain functions
cytoskeleton function
this is a filamentous network that maintains and changes the cell shape as well as produces cell movement. Composed of three different types of filaments microfilaments- actin, contraction intermediate filaments- strength mictotubules filament- neuronal transport mechanisms, centrioles to promote cellular division, flagella and cilia for cell movement
extracellular matrix
this is loose fibrous connective tissue this is a network of inter-cellular proteins that provides a scaffold for cellular attachment composed of elastic, collagen, carbohydrates
triplet code
three bases on DNA, 64, 3 are stop signals
characteristics of epithelial cells
tightly packed cells forming a continuous layer anchored to a basement membrane tight junctions in lumens so particles are impermeable
main steps of gene expression
transcription- DNA to pre-mRNA in nucleus, invovles RNA polymerase binding to promoter region post transcriptional modification involves splicing together of exons and the cutting out of introns via spliceosomes, cytosol translation- floating amino acids are bound to transfer RNA in which the anitcodon matches with the codon on the MRNA strand
integrin
transmembrean proteins in the plasma membrane of one cell which binds to specific proteins in the extracellular matrix or link them to adjacent cells
