Animal Science 2 Midterm 2

What are the main functions of the GI tract?

- receiving

- conducting, storing

- digestion, absorption

- absorbing water, defecating

GI Tract

Gastrointestinal tract

What do Goblet Cells secrete?

Mucus

What do parietal cells secrete?

HCl

What do chief cells secrete?

- pepsinogen, renin, and gastric lipase

What does the salivary glands secrete?

Saliva, which is composed of amylase and bicarbonate

What does the stomach secrete?

Gastric juice, which is composed of pepsinogen,HCl, renin in infants, and "intrinsic factor"

What does the pancreas secrete?

Pancreatic juice, which is composed of trypsinogen, chymotrypsinogen, carboxy-and aminopeptidase, lipase, amylase, maltase, nucleases, and bicarbonate

What does the Gall Bladder secrete?

Bile, to assist with lipid absorption; which is composed of fats and fatty acids, bile salts and pigments, and cholesterol

What does the duodenum secret?

'Succus enteric', which is composed of enterokinase, carboxy-and aminopeptidase, maltase, lactase, sucrase, lipase, and nucleases

What are the two routes that molecules and ions use to transport across the gut epithelium?

1. Transcellular route

2. Paracellular route

Transcellular route

Across the plasma membrane of the epithelial cells

Paracellular route

Across tight junctions between epithelial cells

- are impermeable to large organic molecules from the diet (glucose, amino acids)

Glycocalyx

- thick layers of mucopolysaccharides and glycoproteins

- Provides for adsorption; enzymes that are essential for the final steps of digestion of proteins and sugars

- Cushions and protects cell membrane from chemical injury

- Enables the immune system to recognize and selectively attack foreign organisms

Which nutrients provide energy?

Carbohydrates

Fats

Proteins

When does protein provide energy?

Only when fed in excess quantities or when rations contain insufficient carbohydrate or fat

Which nutrients provide structure?

Fats

Proteins

Minerals

Water

Which nutrients provide regulatory?

Proteins

Minerals

Water

Vitamins

Name some inorganic macro minerals

Calcium

Sodium

Phosphorus

Chlorine

*Macro means more of these minerals are needed

Name some inorganic micro minerals

Cobalt

Iron

Zinc

*Micro means less of these minerals are needed

Name some essential amino acids

Lysine

Valine

Leucine

Name some nonessential amino acids

alanine

serine

proline

Name some nonprotein nitrogen material

urea

biuret

What is a simple fat or lipid?

Fatty acids

What are some compound fats or lipids?

Neutral fats

sterols

Name some pseudo fats or lipids

Vitamins A, D, E, K

Carotene

Name some crude fiber carbohydrates

Polysaccharides (Cellulose, Hemicellulose)

Name some nitrogen- free extract carbohydrates

- monosaccharides (simple sugars)

- polysaccharides (starches)

- water-soluble vitamins (Vitamin C, B-Vitamins)

What is the cheapest nutrient?

Water

What are some functions of water?

- metabolic reactions

- transport

- temperature regulation

- shape

Carbohydrates

- contain carbon, hydrogen, and oxygen

- are a ready source of energy -

- glucose and glycogen can be stored in tissues

- can be hard/ impossible to digest

Lipids

- fats and oils (less O than carbohydrates

- stores 2.25X more energy than carbohydrates on a weight by weight basis

-saturated (no double bonds), mono and polyunsaturated

- some are essential (obtained from diet)

What are essential nutrients?

Nutrients that must be obtained from the diet

What are nonessential nutrients?

Nutrients that can be synthesized by the animal

FACT TO KNOW

Essential and nonessential nutrients vary between species

Proteins

- polypeptides composed of amino acids: C, H, O, & N (only nutrient with nitrogen)

-20 major amino acids; some are essential, most minor

- simple protein, is an amino acid

- complex protein, is an amino acid + other substances

Minerals

- all other elements other than C, H, O, and N

- inorganic (no C)

- form essential component of many complex proteins, iron

Vitamins

- organic nutrient required in trace amounts for specific functions

- 16 known vitamins

- either fat-soluble (A,D,E,& K) or water-soluble (C, thiamin, niacin, & folic acid)

- fat-soluble essential for all animals

- water-soluble essential for mono gastric animals

How are nutrients passively absorbed?

diffusion across membrane

How are nutrients actively absorbed?

with the use of a transporter protein or endocytosis (requires expenditure of energy)

Digestabile energy (DE)

(Gross energy in feed)- (energy in feces)

Total digestible nutrients

TDN

Metabolize energy (ME)

(DE) - (E in urine and gaseous products of digestion)

Net energy (NE)

(ME) - ( E in consumption, digestion, and metabolism in feed)

What is energy used for?

- Maintenance= E used for basal metabolism, voluntary activity, temperature regulation

- Production= E used for reproduction, growth, lactation, fat deposition, etc.

Microbiota

collection of all microbes living inside the gut

Microbiome

microbes, their genetic elements, and interactions with the environment

Metagenome/ Metagenomics

genetic content of a microbial population

Metatranscriptome/ Metratranscriptomics

functions of microbial population

What is in the Rumen?

Bacteria, Protozoa, Fungi

Commensal bacteria blocks pathogenic bacteria

FUN FACT

What does the rumen do?

- make volatile fatty acids (VFA)

- Break plant polysaccharides into simple sugars

- Microbes use glucose as E source to grow (VFA are end-products and a source of energy for cow)

Metagenome

- sequence bacterial genomes

- gene content to imply function

Metatranscriptome

- sequence bacterial mRNA

- expressed genes to imply function

Self vs. non self

every individual makes molecules for self-identification

- these train immune system to identify itself and every thing else is non self

Antigen

an antibody- generator

- induces immune response

- usually on-self origin, pathogenic or not

- protein, carbohydrate

Epitope

a facet of an antigen

- each antigen can have several epitopes

- each epitope can generate an unique antibody

Bone marrow

-site of all immune progenitor cells

- site of B-cell maturation

Thymus

- site of T cell maturation

What are some physical barriers against pathogens?

- unbroken skin, mucus, peristalsis, flushing (tears, saliva, urine), cilia

What are some chemical barriers against pathogens?

- acidic pH (stomach, vagina), sweat, bile salts, digestive enzymes, nonspecific IgA, antimicrobial peptides

What do Paneth cells make?

- defense's, cathelicidins, etc.

*in intestines

Where is lysozyme?

In tears, saliva, and milk

What are some microbial barriers against pathogens?

- competition for space and nutrients

What is passive immunity?

The transfer of maternal antibodies to a fetus across placenta (not true for all species)

Colostrum

- only lasts for a few months

What happens in Innate immunity?

- once the pathogens make contact with epithelial cells, inflammation begins

- PAMPs bind to epithelial cells

- Resident cells recruit more immune cells

- Flush out the pathogen (diarrhea)

Leukocytes (White Blood Cells)

- respond to inflammation

- Neutrophils, Monocytes/Macrophages (MΦ), Dendritic cells (DC) Natural Killer cells (NK)

- Increase WBC production in bone marrow

- Migrate to site of inflammation

- Phagocytosis of dead cells and pathogens

- MΦ, DC and B cells are professional antigen presenting cells (APCs)

What happens when Innate immunity fails?

Adaptive Immunity responds

Adaptive immunity

• MΦ, DC migrate to Peyer's patches (PP) and lymph nodes (LN)

• T cells bind antigens

• T cells activated

What do T cells activate?

- B cells

- B cells bind antigen through B cell receptor

What happens once the infection is controlled?

• Muststopimmuneresponse

• RegulatoryTcellssuppressinflammation • MemoryTandBcellsform

• Lasting immunity against pathogen

How vaccines work

Skeletal muscle

muscle cells band together by connective tissue sheaths that are independent of individual cell membranes

Striated muscle

capable of rapid contractions

-Red (slow twitch): sustained, continued work;

more resistant to fatigue, aerobic

-White (fast twitch): quick movement, fatigues

rapidly, anaerobic

Smooth muscle

- Controlled by the autonomic nerve system

- Does not contract very rapidly

- Lines the hollow organs

- Can be excited by stretching as well as nerve impulse

Epimysium

Connective Tissue, surrounding entire muscle

Perimysium

Connective Tissue, surrounds bundles of 10-20 myocyte

Endomysium

Connective Tissue, surrounding individual myocytes

Fasciculi

Bundles of myocytes

Myocyte

Individual Muscle fibers or Muscle cells

Sarcolemma

Cell membrane of a cell muscle

- plays a key role in the generation and propagation of electric potentials that are responsible for cell contraction

Myofibrils

Functional unit of a muscle cell

- basic units of contraction inside the myocyte and are composed of two types of fibrous proteins

- These proteins run along the length of the muscle fiber and have a microstructure that allows contraction

- When the myofibrils contract, the muscle cell contracts

Sarcomere

Building block unit of a myofibril, adds length

sarcoplasm

cytoplasm of muscle cells

- stores glycogen (for energy) and myoglobin (red color, stores oxygen)

What prenatal factors affect growth?

Litter size

Size and nutritional status of the mother Genetics of the offspring

What postnatal-preweaning factors affect growth?

Nutritional status of the mother Litter size

Initial size and aggressiveness Exposure to disease/parasites

What postnatal-postweaning factors affect growth?

Gender

Genetics

Nutrition Disease/Parasites

Social Stress

Environmental conditions

Development

coordinationofall diverse processes until maturity is reached

Growth Biology

• Pre-natalGrowth

• Post-natalGrowth

• GrowthRegulation

• GrowthandNutrition

• Growth and Reproduction

Hyperplasia

Multiplication of cells

Hypertrophy

increase in cell size

When is the embryonic period?

conception until major organogenesis is complete

When is the fetal period?

end of embryonic period until parturition

Endoderm

innermost of the three germ layers

- gut

Mesoderm

middle of the three germ layers

- muscle, heart, blood

Ectoderm

the outermost of the three germ layers

- cuticle, nervous system