Exam 3 Flashcards
What does the sigmoidal curve represent
It shows cumulative weight is expressed as total weight at any given time
What does the sigmoidal curve look like
Shaped like the letter S and has a stair stepped appearance due to sporadic growth spurts
What is the self accelerating phase of growth
Characterized by exponential growth due to each cell dividing into two daughter cells at a constant rate resulting in rapid growth w/ little complexity
Why does velocity of growth continue to increase during the self accelerating phase
Because there are more and more cells available to divide
Why does the growth rate of the self accelerating phase begin to slow down
Because it becomes difficult to supply each cell w/ nutrients and efficiently remove harmful wastes
What happens when there is a decrease in efficiency during the self accelerating phase
There is an increase in complexity of the cells
How does the embryo respond during the self accelerating phase
By developing increasingly complex transport mechanisms to supply nutrients and removes waste
When does growth become linear
When the acceleration force is in balance w/ the counteracting effects of increased complexity and limited nutrients
What is the point of inflection
The point of maximum growth velocity after which the animal will continue growing but at a decreasing rate
What is another way to look at the maximum growth velocity
It is the period of greatest average daily gain
When does point of inflection occur in many species
Puberty
What is the self decelerating phase
When the animal approaches mature weight at a decreasing rate of growth gradually diminishing the amount of feed intake until energy consumed approaches maintenance requirements
What is one thing that controls the growth rate
Secretion of somatostatin by the hypothalamus
What is asymptote phase
Point at which food intake matches maintenance requirement
What does excess in cells being produced result in during the asymptote phase
Adipose tissue
What fluctuates maintenance requirements once in the asymptote phase
Available food, reproductive cycle, and season
What is the the senescence and death phase
The eventual failure of vital systems results in the loss of body condition and death
When and why does the senescence and death phase typically occur
After the reproductive phase of life and to ensure space for the next generation
What is growth a function of
Chronological and physiological age
What type of growth curves describe growth over time
Cumulative growth, absolute growth, relative growth
What factors can influence the growth curve of chronological age
Nutrition, disease, stress, and activity level
What is important to keep in mind when looking at chronological age
That age is in absolute time units and that animals w/in a species, breed, or gender do not grow, develop, or fatten at the same rate or mature at the same chronological age
What is physiological age used for
Comparing different animals in various species
What does physiological age refer to
Specific physical or chemical stages of maturity including height, weight, composition, and puberty
What is the absolute growth rate curve
Plots gain per unit of time against time
What is the formula for ADG
(Y2-Y1)/(t2-t1)
When is ADG accurate
If the time interval between measurements is short
What is the relative growth rate curve
Growth in relation to total weight that can be used to describe whole body or individual tissues growth
What is the relation to the relative growth curve and the animals age
Relative growth is greatest during the initial stages of development because the animal is so small but as the animal continues to grow relative growth rate decreases
What is the formula for RGR
(lnY2-lnY1)/(t2-t1)
What does the whole body growth curve represent
A sum of growth of many different tissues that develop at dramatically different rates
How do body components develop
In order of physiological importance so nerve, bone, muscle, then fat
What are the first things to develop
Extremities as development occurs from the outside in
What is allometric growth
Proportions of the animal are determined by overall body size
What is the formula for allometric growth
Y=ax^b
What are the basic principles of allometric growth
A constant relationship exists between each tissue/organ and the whole body and the b dictates the slope of the line
What does b>1 indicate
Tissue or component is growing at a faster rate than the whole and has a high growth impetus and are considered late developing tissues
What does b<1 indicate
Tissue or component is growing at a slower rate than the whole and has a low growth impetus and are considered early developing
What does b=1 indicate
Tissue or component is growing at a similar rate than the whole and has an average growth impetus aka isometric growth
What is the relationship between nutrition and allometric growth
When nutrition is limited the tissues have a different priority for nutrients based on their development and functional priority
What does allometric growth curves identify
When muscles develop
What are early developing muscles (b<1)
Distal and proximal thoracic and hind limbs
What are late developing muscles
Abdominal muscles associated with the demand of the rumen and neck to thoracic limbs associated w/ increased weight bearing duties and potential increase from secondary sex characteristics
What are muscles that develop at a similar rate to the rest of the body (b=1)
Muscles surrounding the spinal cord
What changes during growth
Tissue and chemical composition of the body
What are the two ways we can measure changes in tissue or chemical composition
Absolute basis and percent basis
What is absolute basis
Cumulative weight gain over time
What is percent basis
Proportion of the total body weight over time
What is absolute growth
Description of cumulative weight of muscle, bone, and fat over time resembling cumulative sigmoidal growth curves and the timing of each tissues maximum growth differes
What chemicals are bone, muscle, and fat composed of
Water, protein, lipid, and ash
What is percentage growth
Describes muscle, bone, and fat percentage of the whole body typically fat becomes a larger proportion of the body w/ age while muscle and bone make up a smaller proportion
What is the relationship of water content present in muscle w/ age
Water content is greatest early in life and decreases w/ age
What increases w/ age
Absolute and percentage of protein
What is the relationship between the water/protein content in fat cells and age
Water and protein content of fat cells is high early in development and decreases w/ age
What is the relationship between the water and protein content in bone and age
Water and protein content are at their highest early in development and decrease w/ age
how does absolute mineral and fat content change in bone w/ age
They increases w/ age
How does the absolute amount of CT change w/ age
It increases w/ age when associated w/ muscles and tendons
What are the changes seen in collagen and elastin w/ age
They increase significantly w/ muscle development but as a percentage it decreases w/ age
What happens as muscle atrophies w/ age
Percentage of CT increases
What do animals grow in accordance w/
The interactions between the genes they inherit and the environmental factors
What are environmental factors that affect growth
Stress, nutrition, diseases, and activity
What is genetics the science of
Heredity which is the process of passing along genes from one generation to the next
How do genetic differences develop
Through evolution which results from selection of mutations that arise in genes
What is heritability values reflect
The ability of an animal to pass a particular trait to the next generation
What does H> 0.5 indicate
A highly heritable trait
What does 0.2<H<0.5 indicate
A moderately heritable trait
What is H<0.2 indicate
A low heritable trait
How does growth between species vary
W/ the deposition of different tissues and the proportion of each body part
How have species been developed over time
Either natural selection or by man made selection for desirable trait
How has muscle distribution been affected by selection/domestication
Wild species have a greater percentage of muscle on their upper hind legs to enhance speed and agility while domesticated ruminants have greater proportion of muscles in their abdominal cavity
Where is there the most muscle in a pig
Around the spinal column extending the backbone for rooting action
Where is there increased muscle in ruminants
In the front legs to bear weight associated w/ grazing for long periods of time
What is species a major determinant in
The deposition of fat and how it accumulates w/ age
How have breeds devleoped
Animal breeders placed selection pressure on different traits w/in a species
How are cattle breeds selected
By meat and milk or frame size
How is the frame size of an individual animal determined
W/ a frame score
When are larger framed cattle heavier than small framed cattle
At any given compositional and physiological maturity
Why are larger framed cattle considered later maturing
Because it takes them longer to reach their mature weight
Why are small framed cattle considered early maturing
Because they grow relatively quickly reaching their mature weight sooner
What is the relationship between the chronological age of large framed and small framed animals
Larger framed animals are physiologically younger
How are large framed and small framed animals compared using the same chronological age and weight
Large framed animals are leaner while small framed animals are fatter and more physiologically mature
What is the relationship between the selection of muscle versus milk production
They are inversely
How did selection change the muscle that develops prenatally
It doesnt change the muscle distribution it reduces the number of muscle fibers present
What is the relationship between the selection of wool versus meat
They are inversely related
What breeds of sheep have superior conformation
Meat breeds have a higher muscle:bone ratio
What are physical differences between wool and meat breeds of sheep
Wool breeds are larger framed and fattened at heavier weights than meat breeds
What it the relationship between the selection for maternal versus meat in pigs
Muscle is inversely related to the ability to conceive and produce milk
What are the differences in growth and composition across sexes
Intact males are capable of larger body weights, attain compositional maturity at later chronological ages, and are generally heavier at any given chronological age than castrates and females
What are the two exceptions to intact females maturing earliest of sex classes
Gilts mature later and reach heavier weights than barrows and gilts are leaner than barrows at the same chronological age
Where do intact male cattle have a greater proportion of muscle
Their forequarter specifically in the neck and thorax these are associated w/ secondary sex characteristics due to increase androgen binding receptors in these tissues
Where do cows have a greater proportion of muscle
In the pelvic limb and abdominal wall to support fetus and udder
What is the order of muscle diameter
Males have the largest then castrates then females
What does estrogen stimulates in cattle skeletons
Epiphyseal plate closure resulting w/ intact males being taller than females
What do estrogens and androgens increase
Periosteal bone growth (androgens more)
What sex class of cattle has thicker bones
intact males
How are lipogenesis and lipolysis regulated
Hormonally through sex steroids dramatically
How does gender affect fat development
Nutrient drive partition is affected, there is a decrease in long bone growth in females due to an increase in estrogen, and muscle growth starts to decrease leaving more nutrients available for fat
How does nutrition affect growth
Growth and development depends on the level of essential nutrients in the diet such as FA, AA, CHO, vitamins, and minerals
What does consuming nutrients in excess of maintenance requirements allow for
Growth, production, and reproduction
What does the balance of nutrients consumed determine
The composition of growth
What do nutrient maintenance requirements maintain
Vital organs and bodily functions w/ little or no physical activity
What do growth requirements maintain
Body tissues such as muscle, bone, fat, and nerves that are also based on where the animal is in its growth curve including growth of a fetus in pregnant females
What do production requirements maintain
Lactation, wool, eggs, physical activity, reproductive behaviors, and work
What is nutrient partitioning
Utilization of nutrients is partitioned amoung various tissues and organs according to their physiological importance
What are conditions of altered nutrient partitioning
Pregnancy or during the transition from non lactating to lactatin
How does pregnancy alter the nutrient partitioning
The fetus holds priority similar to vital organs of dam however, some wild animals will abort a pregnancy to survive
How does transitioning from non lactating to lactating alter nutrient partitioning
It changes the priority of nutrients from tissue gain to supporting lactation
What is positive energy balance
Nutrients are plentiful for body maintenance, growth, and fattening
What are negative energy balance
Nutrient intake is not sufficient to meet these needs resulting in mobilizing body energy reserves as an energy source
What is compensatory growth
An animal’s growth after a period of nutritional stress where the rate of growth is often greater than exhibited by a genetically identical animal during normal growth also referred to as catch up growth since the increased growth rate allows animals to reach body weights similar to uncompromised animals
What are two ways abnormally high growth rates are achieved
Low basal metabolism during nutrient restriction due to decreased visceral weight and increased feed intake during realimentation
What can affect how much compensatory growth occurs
Severity of nutrient restriction and stage of growth curve where restriction takes place
What does severe starvation cause
Permanent stunt of growth and enhancing the onset of fattening
What can nutrient restriction early in growth result in
Long lasting effects particularly in early maturing tissues such as bone
What two things must be considered w/ dietary protein
Quantity and quality
What does protein quality refer to
The balance and bioavailability of essential AA in a foodstuff
What does biological value measure in dietary protein
The quality and refers to how much protein/AA is absorbed and incorporated into the body
What type of animals are AA more important for
Monogastric animals
What do ruminants utilize for some AA
Rumen microbial protein
What do diets that are sufficient in energy but insufficient in protein result in
Increased fat deposition
How do muscle protein accretion rates vary amongst animals
Breeds, sexes, physical activity, and growth enhancers
What animals have an increased muscle protein accretion rate requiring more protein
Breeds genetically selected for meat production, working animals, males, and hormonally treated animals for growth enhancement
What is dietary energy required for
Maintenance and growth of new tissues
What are energy requirements based on for growth
Genetics, sex class, location on growth curve, and use of hormone treatments
Do animals contain more animal cells or microbial cells
They contain more than 10x microbial cells
What does better sanitation w/ domestic animals lead to
Improved growth rates and feed efficiency
Why does the presence of microoganisms reduce performance
Because it costs more nutrition and energy to build an immune response
What are strategies to limit the effect of microorganisms on growth and performance
High level biosecurity for farms, feeding diets that contain sufficient nutrients to maintain a healthy immune system, vaccinations against the most harmful pathogens, and antibiotic treatments to reduce bacterial load
What does physical and social stress affect
Hypothalmo-pituitary-adrenal axis
What do chronically stressed animals suffer from
Elevated circulating concentrations of glucocorticoids inhibiting growth
What things go into causing transportation stress
Temperature/wind change, novel social group, absence of feed and water, and motions
What causes housing stress
Introducing new animals into a new social order forcing a new social hierarchy to establish
What is specific stress free housing
Rearing animals in a group from weaning to slaughter resulting in less injuries and improved growth
What is considered physical activity
Any body movement that works your muscles and requires more energy than resting
What are available energy reserves in the body
Body fat, muscle fat, muscle CHO, and liver CHO
Where does energy come from for the phosphagen system (short term energy)
ATP in the muscle
Where does energy come from for the glycogen lactic acid system (medium energy)
Muscle + liver glycogen converted to glucose and then lactic acid for anaerobic respiration
Where does energy for the aerobic respiration system come from (long term energy)
Complete oxidation of glucose and FA from muscle, liver, and adipose
What does resistance exercise increase
Muscle protein synthesis
What does endurance exercise do
May decrease protein synthesis if insufficient dietary energy and protein is available
What does increased activity during development increase
Bone mass, density, and size
What type of exercise does fat positively impact
Aerobic
What does exercise induce the release of
IGF-1 and GH in a pulsatile fashion
What type of exercise induces GH release
Resistance and endurance the amount just depends on the intensity
What does GH do to the body when released during exercise
GH is the greatest adolescence greatly impacting mature body size and composition
What is the benefit of immune cells arranging themselves into organs and tissues
So the cells can interact w/ each other through direct contact via chemical messengers and their receptors
What are the two basic components of the immune system
Innate and adaptive/acquired
What is the innate aspect of the immune system
An ancient system present in most eukaryotic life forms, exists in pre-infection/challenge, exhibits broad specificities, and early response to infection
What is the adaptive/acquired aspect of the immune system
Exists only in vertebrates and matures on exposure to antigen
What type of cells are in the Innate system
Granulocytes, natural killer cell, macrophage cell, dendritic cell, and mast cells
What cells are found in the adaptive immune cells
B cells and T cells
What are Granulocytes
Neutrophil, eosinophil, and basophils are designed to destroy infected cells or pathogens
What are natural killer cells
Kills cells that are infected or have things wrong w/ them
What are macrophage cells
Garbage disposal cell eating infected or dead cells
What are dendritic cells
Primarily used to identify parts of microbes and present them to cells in the adaptive immune system
What are mast cells
Packed w/ histamines which are good at fighting off extra cellular pathogens and are responsible for seasonal allergies
What are B cells
Producers of antibodies
What are CD8+ T cells do
Expresses cytotoxic cells that kill infected cells
What are CD4 T cells do
Release messengers that express other cells
What happens in bone marrow
Hematopoiesis of myeloid and lymphoid
What occurs in the central lymphoid organs
Maturation of lymphocytes such as bone marrow for B cells and thymus for T cells
Where do all immune cells stem from
A blood stem cell where division into either myeloid or lymphoid stem cells occur
How do autoimmune diseases occur
When T cells recognize the indivuidual’s own cells too strongly
What is the process of thymocyte development
BM derived T cell precursors arrive in the outer cortex of the thymus where they go thru selection, proliferation, and apoptotic death as they move thru the cortex, few cells mature and moving out of the medulla, and during this process they acquire their diverse specificity including surface receptors and markers
What are the different classes of lymphocytes
B lymphocytes, helper T lymphocytes (CD4+), Cytotoxic T lymphocytes (CD8+), Natural killer cells (NK), Natural killer T cells (NKT), and Gamma delta T cells
What is the function of Helper T lymphocytes
Activation of macrophages, inflammation, and activation of T and B lympocytes
What is the function of cytotoxic T lymphocyte (CTL)
Killing of infected cells
What is the function of regulatory T lymphocytes
Suppression of immune response
What is the function of Natural Killer (NK) cells
Killing of infected cells
Where do immune responses occur
Lymph nodes, spleen, cutaneous immune system, and mucosal immune system
What is the center of the lymph node called
Medullary sinus
What is located at the bottom of each section of a lymph node
Medullary cords made of macrophages and plasma cells
What is the middle of each lymph node section called
Paracortical area which is mostly T cells
What is the top of the outer lymph node sections called
Primary lymphoid follicle which is mostly B cells
What is the top of the inner lymph node sections called
Seondary lymphoid follicle w/ germinal center
What is the function of the outer afferent lymphatic vessels
Brings material in the lymph node
What is the function of the inner efferent lymphatic vessle
Takes material out of the lymph node
What are the functions of the spleen
Major site of immune responses to “blood boren” antigens/infections, is hematopoietic, and is a lympoid
What is the red pulp of the spleen
Destruction of old RBCs
What is the white pulp in the spleen
Used as a lymphoid for immune responses, contains periarteriolar lymphoid sheaths (T cells) and lymphoid follicles (B cells)
What cells does the cutaneous immune system contain
Keratinocytes, epidermal langerhans cells, intraepithelial lymphocyte (CD8+), basal keratinocytes, plasma cells, mast cells, macrophage, t lymphocytes (CD4+), and dermal dendritic cell
What is different about the mucosal immune system in the intestine
Their are specialized dendric cells that have tentacles that take microbes thru the epithelial layer to the draining lymph node, IgA is specialized, and Peyers patches are present pushing up against the gut producing M cells that lets gut fluid leak into the patch bringing in B and T cells
What are non lyphoid players
Antigen presenting cells such as dendritic, circulating monocytes, and macrophages
What is the function of circulating monocytes
Cells found in the blood that can turn into dendritic and marcophages
What is the function of humoral immunity
Block infections and eliminate EC microbes
What are the functions of cell mediated immunity
Activate macrophages to kill phagocytosed microbes and to kill infected cells and eliminate reservoirs of infection
What can be transferred w/ passive immunity
Antibodies or lymphocytes
What is the difference between active vs passive immunity
W/ active immunity a microbial antigen challenges the immune system which recovers producing immunity while passive immunity involves serum from an immune individual being administred to an uninfected individual
What is the relationship between adaptive immunity and innate immunity interact
Innate immunity often begins the process of adaptive immunity, adaptive immunity can augment the abilities of innate immunity, and innate immunity can extend the functions of adaptive immunity
How does the innate immunity enhances effector functions of the adaptive immunity
Stimulation of an effective immune response usually requires more than just a signal provided by the antigen and can be a soluble product or a surface ligand on an accessory cell
What is the clonal selection process initiated
By recognition of foreign antigens by antigen specific lymphocytes
What does the adaptive immunity lead to
Activation, proliferation differentiation, effector functions, and homeostasis
What is an antigen
A molecule that binds specifically w/ an antibody or T cell receptor
What is an epitope
The actual part of an antigen that binds to an Ab or T cell receptor binding site
What are multiple epitopes called
Multivalent antigens
What are the types of epitope determinants that are recognized by antibodies
Conformational determinant, linear determinant, and neoantigenic determinant
What is an adjuvant
A compound that is given with an antigen when immunizing a host, to augment the immune response achieved
What are the functions of antibodies
Revome the antigen via precipiatation or iducing phagocytosis, neutralize the antigen , kill the organism expressing the antigen, or triggers hypersensitivty reaction
What are the three main components of the immunoglobulin structure
Light chain, disulfide bonds, and heavy chains
What is the difference between a heavy chain and a light chain
A light chain has a fab fragment while a heavy chain has an fc fragment
How many light chains are on the immunoglobulin structure
2
What is the basic structure of the antibody
Two symmetrical branches each made up of 2 identical light chains and two identical heavy chains
Where are the chains attached and how are they attached in an antibody
One light chain is covalently attached to one heavy chain by S-S bonds and the two H chains are attached to by S-S bonds
What are the functions of the variable regions between the light and heavy chains of an antibody
They recognize epitopes, make the antibody combining site, and are the specificity
What does the N terminal Ig domain of each light and heavy chain contain
3 hypervariable regions called Complementarity determining regions (CDRs)
What do CDRs demonstrate in the 10 AAs
Extremely high variability
How many CRDs are in each chain
3
What is the antibody combining site
Where the hypervariable loops formed by the CDR extends from the surface of the Ab
What is the Ig constant region
At the C terminal of the heavy and light chains comprised of Ig domains has little variability, does not interact w/ antigens or epitopes, where most of the biological functions of antibodies are mediated, and where the isotype of the Ig is located
What is the hinge region on heavy chains
Located between CH1 and CH2 allowing for flexible molecular motion and has different lengths for different isotypes
What are the two names for light chain c regions on an Ig
Keppa and lambda
What cells of antibodies does a membrane form
B cells that make the antibody
What are the secreted forms of IgG and IgE
Monomeric
What are the secreted forms of IgA and IgM
Covalently bound multimers
How are IgA and IgM bound together
Through the tail pieces at the carboxy end of the M and A heavy chains along with a J piece w S-S bond to the tail piece
What are the important characterisitics of antibodies
Bi valent, flexible, membrane form is B cell receptor, acts thru out body, V regions combine w/ antigens in a highly specific manner, and c regions of their heavy chains interact w/ multiple cell types/soluble inflammatory molecules mediating the effector function
What is the synthesis, assembly, and expression of immunoglobulins
Synthesized on membrane bound ribosomes and glycosylated in the RER, once assembled they move to the golgi complex for modifications of their CHO molecules, then are transported to the plasma membrane in vesicles and either anchored or secreted
What are the changes that occur in the antibody structure
Affinity maturation, changed to secreted form, and switching the isotype
What is monoclonal
Each B cell makes antibodies of one specificity essentially they are all clones
What is polyclonal
One thing containing lots of groups of antibodies varying in specificity such as serum
What is affinity maturation
A process that yields antibodies that bind tightly to their antigen, involves subtle changes through somatic mutations in antigen stimulated B cells that produce new V regions, B cells w/ higher affinity receptors are selected by dominant antigens, and raises the avg binding affinity of the antibodies that make antigens
What is antibody specificity
Distinguishes between linear protein determinants that differ by a single conserved AA in their sequence potentially the epitope might be part of multiple antigens, and cross reactions occur when an antibody combines w/ multiple epitopes when specificity is low
When does a cross reactivity of antibodies occur
When some parts of an antigen are shared by another antigen
What is antibody affinity
The pure measure or the on/off rate between the antigen and the antibody combining site
What is antibodiy avidity
True overall strength of the attachment of the antibody and antigen
What is ELISA set up for
To quantify the concentration of antigens
What are the parts of the MHC complex
T cell receptor, peptide, and MHC
How was the MHC discovered
Through transplantation studie
What are genes produced in the MHC region responsible for
Rapid rejection of tissue grafts
What is MHC
Polymorphic
What is syngeneic in terms of inbred mice
If you inbreed sibling mice for about 20 generations all the offspring are essentially genetically identical and will accept each others tissue graphs
What is allogeneic in terms of inbred mice
Different inbred strains that will not accept tissue grafts from another inbred strain
What is congenic in terms of inbred mice
Identical at all loci except the trait that you select so you bred them. Developed by a cross between 2 inbred strains
What is MHC’s real job
Extended genetic locus that contains several highly polymorphic genes that encode highly polymorphic cell surface proteins and present antigen epitopes to TCRs that are recognized together w/ the epitopes by the TCR
What is the difference between MHC class 1 and MHC class 2
They sample different pools of epitopes and present them to different subsets of T cells but they are structurally distinct and both are polymorphic
What is a haplotype
Genes w/in the entire MHC region of the genome are sufficiently close together so they are mostly inherited together
What are class one MHC molecules present in
Epitopes to CD8+ T cells expressed on all nucleated cells on the body
What are class 2 MHC molecules present in
Epitopes to CD4+ T cells and are expressed on APCs: macs, dendritic cells, and B cells often differentially regulated
What are general features of MHC molecules
Consists of an EC peptide binding groove, is anchored thru a transmembrane and cytoplasmic domain, polymorphism is due to AA residues in and adjacent to the peptide binding groove, and their non polymorphic EC Ig domains contain binding sites for the T cell surface markers CD4 and CD8
What is the peptide binding cleft like for MHC class 1 molecules
They are closed at the ends forming a pocket for the Ag peptide
What is the peptide binding cleft lie for MHC class 2 molecules
The are open at the ends so that peptides can hang outside of the cleft
What controls the specificity of the MHC peptide binding
T cell receptor (TCR)
What kind of peptides bind in the pockets of the MHC cleft
Ones that have anchor AA residues
What else are class 2 MHC molecules expressed in
The up regulation by cytokines during both innate and adaptive immune responses
What does IFN gamma increase
MHC expression and antigen presentatoin
