Chapter 39 Butterfly Biology Complete PPT

1. Unit 10 The Human Body
Ch. 39 Endocrine & Reproductive
Systems

2. The Endocrine System
 The endocrine system is made up of
glands that release their products into the
bloodstream
 These products deliver messages
throughout the body

3. Hormones
 Hormones - chemicals released in 1 part
of the body, that travel through the
bloodstream, & affect activities of cells in
other parts of the body; “chemical
messengers”
 Target cells (receptor cells) - cells that
have receptors for a particular hormone

4. Glands
 A gland is an organ that produces &
releases a substance, or secretion
 Exocrine glands - release their secretions
(hormones) through ducts (tubes), directly
to the organs that use them

5. Glands
 Endocrine glands - release their secretions
(hormones) directly into the bloodstream

6. Major Endocrine Glands

7. Hormone Action
 Steroid hormones:
 Because they are lipids, they
can cross cell membranes,
passing directly into the
cytoplasm & the nuclei of
target cells

8. Hormone Action
 Nonsteroid hormones:
 They generally cannot pass
through the cell membrane of
their target cells

9. Prostaglandins
 Prostaglandins - modified fatty acids that
produce cells, affecting other nearby cells
& tissues (“local hormones”)
 Ex.) some cause smooth muscle tissue to
contract

10. Control of the Endocrine
System
 Like most systems of the body, the
endocrine system is regulated by feedback
mechanisms that function to maintain
homeostasis
 Ex.) Pancreas releasing insulin: blood sugar
level increases after lunch, pancreas releases
insulin, blood sugar level decreases,
pancreas stops releasing insulin

11. Human Endocrine Glands
 The human endocrine system regulates a
wide variety of activities
 Any improper functioning of an endocrine
gland may result in a disease or disorder

12. Human Endocrine Glands
 The major glands of the endocrine system
are: the pituitary gland, the hypothalamus,
the thyroid gland, the parathyroid glands,
the adrenal glands, the pancreas, & the
reproductive glands

13. Pituitary Gland
 Pituitary gland - divided into 2 parts:
anterior & posterior; it secretes 9
hormones that directly regulate many body
functions & controls the actions of several
other endocrine glands

14. Pituitary Gland Hormones

15. Hypothalamus
 The hypothalamus controls the secretions
of the pituitary gland
 The close connection between the
hypothalamus & the pituitary gland, means
that the nervous & endocrine systems can
act together to help coordinate body
activities

16. Thyroid Gland
 The thyroid gland has the major role in
regulating the body’s metabolism
 Releases thyroxin which increases
metabolism, & cellular
respiration

17. Thyroid Gland
 Unable to produce thyroxin produces
condition known as cretinism
 2 effects of cretinism are dwarfism &
severe mental retardation
 Can be prevented by adding small
amounts of iodine to table salt

18. Parathyroid Glands
 The 4 parathyroid glands are found on the
back surface of the thyroid gland
 Hormones from the thyroid gland & the
parathyroid glands act to maintain
homeostasis of calcium levels in the blood

19. Adrenal Glands
 There are 2 adrenal glands that sit on top
of the kidneys, like little hats
 The adrenal glands release hormones that
help the body prepare for & deal with
stress

20. Adrenal Glands
 The 2 hormones secreted by the adrenal
glands are: epinephrine and
norepinephrine
 The hormones produce the “fight or flight”
response to stress

21. Pancreas
 The pancreas has both exocrine &
endocrine functions
 It is a digestive gland whose enzymes help
break down food
 However, different cells in the pancreas
release hormones into the blood

22. Pancreas
 Insulin & glucagon are released from the
pancreas to help keep the blood glucose level
stable
 Insulin stimulates liver cells to remove sugar
from the blood & store it as glycogen
 Glucagon stimulates the liver to break down
stored glycogen & release sugar back into the
blood

23. Pancreas
 Diabetes mellitus - when the pancreas
does not produce insulin
 There are 2 types of diabetes, Type I and
Type II
 Type I requires daily injections of insulin,
due to the fact that the body produces no
insulin

24. Pancreas
 Type II develops in people after the
age of 40, produces normal insulin but
cells don’t respond properly to the
hormone
 Usually controlled through diet,
exercise, & medication taken orally

25. Reproductive Glands
 The gonads are the body’s reproductive
glands
 They serve 2 important functions: the
production of gametes & the secretion of
sex hormones

26. Reproductive Glands
 The female gonads are the ovaries - which
produce eggs, & the hormones estrogen &
progesterone
 The male gonads are the testes - which
produce sperm, & the hormone
testosterone

27. The Reproductive System
 Reproduction is the formation of new
individuals
 If any other system of the body failed, the
result would be fatal, not the case with the
reproductive system
 Reproduction is important for continuation
of the species, but not for that organism to
survive

28. Sexual Development
 For the 1st 6 weeks of development, male
& female embryos are identical
 During the 7th week, primary reproductive
organs begin to develop
 Hormones produced by those organs
(gonads), will determine whether the
embryo develops physically into a male or
female

29. Sexual Development
 Neither the testes nor the ovaries are
capable of producing active reproductive
cells until puberty
 Puberty - a period of rapid growth & sexual
maturation, when the reproductive system
becomes fully functional

30. The Male Reproductive System
 The main function of the male reproductive
system is to produce & deliver sperm
 Scrotum - external sac that holds the
gonads, (external to reduce heat so sperm
won’t die)
 Seminiferous tubules - tiny tubules tightly
coiled where the sperm are produced

31. The Male Reproductive System
 Sperm - male sex cells (gametes)

32. The Male Reproductive System
 Epididymis - structure that sperm move
into, to mature & be stored until released
 Vas deferens - tube that carries sperm
from the epididymis, to the urethra, to be
released
 Penis - urethra carries sperm out of body
through the penis

33. The Male Reproductive System

34. The Female Reproductive
System
 The main function of the female
reproductive system is to produce ova
(eggs)
 In addition, the female reproductive
system prepares the female’s body to
nourish a developing embryo

35. The Female Reproductive
System
 Follicles - each ovary contains 400,000
clusters of cells surrounding a single egg,
to help it mature
 Ovulation - when a follicle has completely
matured, its egg is released

36. The Female Reproductive
System
 Egg - female sex cells (gametes)
 Fallopian tubes - tube from each ovary,
that carries the egg to the uterus

37. The Female Reproductive
System
 Uterus - location of egg a couple days
after ovulation, where embryo develops if
fertilization takes place
 Cervix - the outer end of the uterus
 Vagina - a canal that leads to the outside
of the body

38. The Female Reproductive
System

39. The Menstrual Cycle
 Menstrual cycle - when an egg develops &
is released from an ovary
 The menstrual cycle has 4 phases:
follicular phase, ovulation, luteal phase, &
menstruation

40. The Menstrual Cycle
 The Follicular Phase
 Development of an egg
 Ovulation
 Lasts 3-4 days, a mature egg
is released into 1 of the
fallopian tubes

41. The Menstrual Cycle
 Luteal Phase
 The remaining ruptured follicle, which
continues to release hormones
 Menstruation - when the lining of the
uterus sheds, lasts about 3-7 days (period)

43. Sexually Transmitted Diseases
 Sexually transmitted diseases - diseases
spread from 1 person to another through
sexual contact
 Common STDs are chlamydia, syphilis, &
gonorrhea (caused by a bacteria)

44. Sexually Transmitted Diseases
 Others caused by viruses include: HIV,
hepatitis B, genital herpes, & genital warts

45. Fertilization
 When an egg is fertilized, the process of
human development begins
 In this process, a single cell, the size of a
period at the end of a sentence,
undergoes cell divisions that
results in the formation of
a new human being

46. Fertilization
 Fertilization - the process of a sperm
joining an egg, usually occurs in the
fallopian tube
 Zygote - a fertilized egg

47. Early Development
 The stages of early development include:
implantation, gastrulation, & neurulation
 Implantation - when the blastocyst
implants itself in the uterine wall
 At this point, cells differentiate - develop
into specific types of tissues in the body

48. Early Development
 Gastrulation - the formation of 3 cell
layers; the beginning of all of the organs &
tissues of the embryo will form from these
3 layers

49. Early Development
 Neurulation - the development of the
nervous system, occurs shortly after
gastrulation

50. Early Development
 Placenta - connections between mother &
developing embryo
 The embryo needs a supply of nutrients &
oxygen, & a way to get rid of carbon
dioxide & wastes
 Nutrients & oxygen diffuse from the
mother’s blood into the baby’s blood

51. Early Development
 At the same time, carbon dioxide &
metabolic wastes diffuse from the baby’s
blood into the mother’s blood, to be
excreted
 The placenta is the embryo’s organ of
respiration, nourishment, & excretion

52. The Placenta

53. Early Development
 Fetus - after 8 weeks of development, the
embryo is then called a fetus
 The umbilical cord connects the fetus to
the placenta
 Pregnancy, is divided into 3 trimesters,
during the 3rd, the organ systems mature,
& the fetus grows in size & mass

54. Later Development

55. Childbirth
 After 9 months, the fetus is ready for birth
 Oxytocin, a hormone released from the
pituitary gland, causes contractions to
begin
 The contractions become more frequent &
powerful

56. Childbirth
 The cervix opening expands until it is large
enough for the baby’s head to pass
through
 Contractions of the uterus force the baby
out through the vagina