7 - Animal Digestion (Lactation) Flashcards
What hormones primarily regulate lactation
Estrogen, progesterone, and prolactin
Why does lactation begin after birth
The abrupt decline in estrogen and progesterone after birth removes their inhibitory effect, allowing prolactin to stimulate milk production
What is the evolutionary origin of mammary glands
Likely evolved from ancestral apocrine-like skin glands
What structural adaptations support suckling in mammals
Secondary (hard) palate, soft tissues and cheeks for suction, two sets of teeth, and reduced cervical ribs for neck flexibility
Why do mammals only have two generations of teeth
To accommodate prolonged suckling and jaw development
What are the key advantages of lactation and suckling (5)
Efficient maternal energy use
Supports rapid growth and high metabolic rate
Provides immunity
Encourages taste learning and food preference
Builds social bonds and enables learning
What are the basic components of milk
Water, fat, carbohydrates (mainly lactose), proteins, and minerals
How does milk composition vary within an individual
Varies with circadian rhythm and stages of lactation (e.g. colostrum to mature milk; foremilk vs. hindmilk during a feed)
How does milk composition vary between species
Species with faster-growing young (e.g. elephant seals) produce milk high in protein and fat
How is milk composition related to offspring growth rate
Faster-growing species produce milk richer in protein and fat
How do small mammals’ metabolic rates relate to lactation
Small mammals often have higher metabolic rates and faster growth, needing richer milk
How does milk help in harsh environments
Concentrated milk aids water retention and nutrient supply, critical in arid conditions
How does lactation differ in placental mammals
Shorter lactation period; milk produced simultaneously across multiple teats
How does lactation differ in marsupials
Longer lactation period; teats can produce different types of milk for differently aged young (double suckling)
