12.3 - pregnancy

what is the period of pregnancy called and how long does it last

gestation → usually takes about 280 days (based on the last menstrual period)

what does the embryo look like after the first month of development (5 things)

• muscle segments that will be brain and spinal cord → 30 pairs that represent vertebrae

• brain beginning to form

• tail evident

• heart and liver starting to develop

• throat has pharyngeal arches with clefts between them

  • arches become structural elements of face and throat

  • pouches in clefts become throats epithelial linings and glands

what appears at the 5th week

arm and leg buds (Arm buds first)

what does the embryo look like at the end of the embryonic period

• recognizable human

• all organs present

• head half the size of embryo

• eyes like slits

• jaw, nose, earlobes, arms, legs, hands, fingers, toes, and external sexual organs all developing

what happens at month three (5)

• limbs developed

• eyelids closed

• outer ear complete

• bone marrow formed with blood cells

• sex distinguishable

what happens at month 4 (4)

• arms and hands fully shaped

• skeleton done

• baby starts moving

• ears stand out from head

what happens at month 5 (3)

• fine hair covers body

• gripping reflexes

• increased growth

what happens at month six (4)

• respiratory movements

• digestive glands start tryna function

• tooth buds

• eyebrows and eyelashes

what happens at month 7 (2)

• period of greatest growth

• all systems functional except respiratory

what happens at month 8 (2)

• fat beneath skin

• growth slowed

what happens at month 9 (4)

• eyes open

• nose well formed

• sucking and grasping

• fine body hair shed

why does the abdomen grow in pregnancy

uterus size, internal organs forced up and out

why do the breasts grow in pregnancy

milk secreting tissues are developing and increasing in size

what are three other ways pregnancy affects the body

• increase in heart size and blood volume

• increased urine due to increased blood flow

• emotional state affected due to hormones and natural fears