Lactation

mammals

animals with hair and mammary glandsthat produce milk to feed their young

monotremes

egg-laying mammals that ack placenta; produce milk from ducts in skin

Marsupials

mammals that have “premature” birthand carry and nurse their young in pouches until fully developed

fetus in utero

completely dependent on mother’s blood for everything; but not eating or digesting

young mammals

structurally imature; immature digestion and metabolic systems; immature immune and other protective systems

milk is a source of:

nutrients, protective factors (antibodies), growth factors.

dairy animal

one that produces milk for the use of humans; milk is harvested for food; produces: milk, cheese, yogurt, ice cream, butter, etc.

main milk components

water, lactose, lipid, proteins, minerals, vitamins

who lactates

mammals

what lacates

mammary gland

where does lactation happen

ventral area

when does lactation happen

after offspring birth

why does lactation happen

to provide for the neonate

milk is complex

emulsion of fat globules; and suspension of leukocytes/cells in plasma membrane; a colloid of caseein micelles in the milk; composed of all water soluble components

emulsion

a liquid dispersed in an immiscible liquid (incapable of mixing to homogeneity)

homogenization

stabilizes the fat emulsion, breaks large fat globules to smaller ones

casein micelles

a colloid in the aqueous faraction

colloid

small particles in a liquid

disruption of micelle structure

formation of curds which allow for cheese formation

fat

most variable milk component

lactose

lease variable milk component

composition varies because:

species, strian or breed, stage of lactation

immunoglobulins in milk

proteins found in body fluids that neurtralize pathogens; some get from placents, ruminants and other animals get it form colostrum, needed to fight disease; provides neonate immunity

passive immunity

adiministration or ingestion of immunoglobulins

active immunity

animal produces anitbodies following exposure to pathogen or immunogen

udder

used in ruminants for all glands

cows

4 mammary glands, 4 teats, one udder

inguinal canal

conduit for blood, lymph and nerves

median suspensory ligament

attaches to abdomen, holds majority of weight

lateral ususpensory ligament

attaches to tendons-pelvis

teat cistern

hold 1 ounce, annulur fold at top

galnd cistern

collect milk from 15-20 ducts

alveoli

milk secreted, lumen holds >50% milk, oxytocin sensitive, several lobules form 1 lobe

importnat for production

blood (500 units/unit milk), lymphatic system

lymph

colorless fluid that drains from tissue spaces

lactose

major carbohydrate in milk, disaccharide, produces only by mammary gland,draws water into milk, digested by intestional lactase

milk fat

synthesized in smooth ER, mostly triglyceride

milk protein

chains of amino acids

casein

most abundant protein, only made in mammary gland, easy to digest, high quality, with fat forms curd

whey proteins

lactoglobulin, lactalbumin, albumin, immunoglobulins, lactoferrin

vitamins and minerals

A,D,E,B vitamins, Ca, PO4-

mammary epithelial cells

make milk components from blood precursors; transport blood components into lumen

mammary gland development stages

fetal, prepubertal, pubertal, pregnancy, lactation

pubertal mammary gland

growth driven by cycles of elevated estrogen, followed by elevated progesterone

mammary development during pregnancy

greatest increase in mass, from simultaneous elevation of estrogen and progesterone, exponential

mammogenic hormones of importance

prolactin, growth hormone, placental lactogen(goats), relaxin(swine)

initiation of lactation

cellular and enzematic differentation of alveolar cells, copius milk secretion

progesterone

inhibits lactogenessis

prolaction

stimulates lactogenesis

grlucocorticoid hormone

stimulates lactogenesis

galactopoiesis

maintenance of lactation (hormones, removal of milk)

removal of milk result

removal of feedback inhibitor of lactation, decreases intramammary pressure, stimulates proalaction secretion surge

milk ejection

oxytocin travels in blood to the ammmary gland and causes contraction of myoepitelial cells that surround alveolus, resulting in ejection of milk from alveolar lumen (1 minute response)

Mastitis

immune reaction of mammary gland to bacterial, chemical, thermal or mechanical injury, inflammatory resposne (increase in blood proteins, immune cells, attacks bacteria nad repairs damage) more somatic cells is an indicator

mammary involution in dry period

alveoli and ducts degeneration, dairy cows given 45-60 day dry period

mammogenesiss

grwoth and dvelopment of the mammary gland

lactogenesiss

initiation of milk secretion

galactopoiesis

maintenance of enhancement of established lactation

alveolus

the basic structural unit in the mammary tissue that produces milk

milk secreation

syntesis of milk of the mammary epithelia cells and passage of milk from the cell into the alveolar lumen

milk removal

passive removal of milk the from the mammary gland cisterns and ejection of milk from the alveolar lumen

mamary growth

in response to ESTROGEN, progesterone, prolaction

lactogenesis in response to:

PROLACTIN, glucocorticoid hormones, decrease in progesterone

glactopoiseis in response to:

MILK REMOVAL, prolactin, other galactopoitic hormones (somatotropin)