Chapter 11 Flashcards Preview

OAT- Biology > Chapter 11 > Flashcards

Flashcards in Chapter 11 Deck (148)
Loading flashcards...
1
Q

What are the two roles of the testes?

A

(1) Synthesis of sperm (spermatogenesis) (2) Secretion of male sex hormones into the blood stream

2
Q

Site of spermatogenesis within the testes

A

Seminiferous tubules;

3
Q

Sustentacular cells

A

Walls of the seminiferous tubules are formed by cellls called sustentacular clues They protect and nurture the developing sperm, both physically and chemically

4
Q

What are important cells found in the testicular interstitium?

A

Interstitial cells (also known as Leydig cells); They are responsible for androgen (testosterone) synthesis

5
Q

Where does the seminiferous tubule empty into?

A

Epididymis; a long coiled tube located on the posterior of each testicle

6
Q

Where does the epididymis from each testicle empty?

A

Into a duct deferens which leads to the urethra

7
Q

What path does the duct deferens travel to get to the urethra?

A

It enters the inguinal canal –>joins the duct of the seminal versicle to form the ejaculatory duct –> joins the urethra

8
Q

Seminal vesicles

A

A pair of glands located on the posterior surface of the bladder that nourish sperm They secrete about 60 percent of the total volume of the semen into the ejaculatory duct

9
Q

What are the three glands that produce semen?

A

The seminal vesicles, the prostrate and the bulbourethral glands Collectively called accessory glands

10
Q

Prostate gland

A

Nourishment, allows semen to coagulate after ejaculation

11
Q

Bulbourethral glands

A

Lubricate urethra, neutralize acids in the male urethra and female vagina

12
Q

Erectile tissue

A

Composed of modified veins and capillaries surrounded by a connective tissue sheath Blood accumulates at high pressures

13
Q

Three compartments contain erectile tissue

A

The corpora cavernosa (two of these) and the Corpus spongiosum (one of these)

14
Q

Three stages of the male sexual act

A

Arousal, orgasm and resolution

15
Q

The sexual act events are controlled by an integrating center in the spinal chord, how is it activated/inactivated?

A

The cerebral cortex can activate this integrating center (in sexual arousal during sleep) or inhibit it (anxiety with sexual function)

16
Q

What is arousal dependent on?

A

The parasympathetic nervous input and can be subdivided into two stages: erection and lubrication

17
Q

Erection

A

Involves dilation of arteries supplying the erectile tissue. This results in swelling which obstructs venous outflow and causes the erectile tissue to become pressurized with blood

18
Q

Lubrication

A

Function of the parasympathetic system. Bulbourethral glands secrete a viscous mucous which serves as a lubricant

19
Q

What is required for an orgasm?

A

Stimulation by the sympathetic nervous system which can be divided into two stages: emission and ejaculation

20
Q

Emission

A

Propulsion of semen into the urethra by contraction of smooth muscles

21
Q

Ejaculation

A

Semen is propelled out of the urethra by rhythmic contractions of muscles surrounding the base of the penis

22
Q

Resolution (2-3 minutes)

A

Or “returning to normal”, unstimulated state, is also controlled by the sympathetic nervous system Caused by a constriction of erectile arteries which results in decreased blood flow to the erectile tissue and allows veins to carry away trapped blood

23
Q

Gametogenesis

A

Process by which diploid germ cells undergo meiotic division to produce haploid gametes

24
Q

Syngamy

A

Fusion of sperm with the egg. The gametes produced by males and females differ dramatically in structure but contribute equally to the genome of the zygote

25
Q

Spermatogenesis

A

Sperm synthesis. It begins at puberty and occurs in the testes throughout adult life

26
Q

What is the site of spermatogenesis?

A

In the seminiferous tubule Spermatogenesis occurs with the aid of the specialized sustentacular cells found in the walls of the seminiferous tubule

27
Q

Where are immature sperm precursors found?

A

The outer wall of the tubule

28
Q

Where are nearly-mature spermatozoa’s deposited?

A

In the lumen and the they are transported into the epididymis

29
Q

Germ cells

A

Give rise to male and female spermagonia Can germinate and give rise to full organisms

30
Q

Spermatogonium Job

A

(1) Mitotically reproduce prior to meiosis (2) Replicate DNA in S phase of meiosis “SpermatoGONium is GONNA become a sperm”

31
Q

Primary spermatocyte job

A

Meiosis I “Any gamete precursor (male or female) with “cyte” undergoes a meiotic division”

32
Q

Secondary spermatocyte job

A

Meiosis II “The secondary spermatoCYTE undergoes the second meiotic division”

33
Q

Spermatic Job

A

Turn into a spermatozoan “The spermatid’s a kid, almost mature”

34
Q

Spermatozoan Job

A

Finish maturing: (1) in seminiferous tubule (2) in epididymis “Just remember that a mature sperm is called a spermatozoan”

35
Q

Where do the final stages of sperm maturation occur?

A

In the epididymis

36
Q

Where do spermatids develop?

A

Spermatids develop into spermatozoa in the seminiferous tubules with the aid of sustentacular cells

37
Q

Acrosome

A

Contains lytic enzymes needed for penetration of the ovums protective layers

38
Q

Bindin

A

Protein that allows for attachment to receptors on the zone pecullia surrounding the ovum

39
Q

Process by which spermatids develop into spermatozoa?

A

(1) DNA condenses and cytoplasm shrinks to from a head (contains haploid nucleus) (2) Flagellum forms tail (3) Neck region carries mitochondria

40
Q

Testosterone

A

Plays the essential role of stimulating division of spermatogonia

41
Q

Luteinizing hormone (LH)

A

Stimulates the interstitial cells to secrete testosterone Secreted by anterior pituitary gland and uses systematic circulation to reach its target

42
Q

Follicle stimulating hormone (FSH)

A

Stimulates the sustenacular cells which support and nourish sperm in seminiferous tube

43
Q

Inhibin

A

Is secreted by sustenacular cells; its role is to inhibit FSH release

44
Q

Wolffian ducts

A

Can develop into male internal genitalia (epididymis, seminal vesicles, and ductus deferens) Can develop into either genitalia

45
Q

Müllerian ducts

A

That can develop into female internal genitalia (uterine tubes, uterus and vagina) Müllerian ducts are the default

46
Q

Although external genitalia is also default, it is not

A

Derived from the Müllerian ducts

47
Q

Genetic information on Y chromosomes leads to the development of

A

Testes, which cause male internal and external genitalia to develop by producing testosterone and Müllerian inhibiting factor (MIF)

48
Q

Müllerian inhibiting factor (MIF)

A

Causes regression of Müllerian ducts

49
Q

Dihydrotesterone

A

Testosterone enters the systemic circulation and is converted into dihydrotestosterone in target tissues in order to exert its effects.

50
Q

Three main fetal precursors of the reproductive organs are

A

Wolffian ducts, Müllerian ducts and the gonads Structures arising from these ducts tend to have the same function

51
Q

Analogous structures

A

Wolffian ducts and Müllerian ducts arise from different precursors

52
Q

Homologous structures

A

Derived from the same underdeveloped structure i.e. Gonads

53
Q

Androgens

A

All hormones involved in the development and maintenance of male characteristics

54
Q

Estrogens

A

All hormones involved in development and maintenance of female characteristics

55
Q

What happens to testosterone after birth

A

levels of testosterone fall to negligible levels until puberty, at which time increases and remains high for the remainder of adult life

56
Q

Secondary sexual characteristics

A

Maturation of the geneticist,male distribution of facial and body hair, deepening of the voice and increased muscle mass. Pubertal growth spurt and fusion of the epiphyseal also results

57
Q

Why is estrogen required at the beginning of puberty?

A

Required to regulate the uterine cycle and for the development and maintenance of female secondary sexual characteristics Maturation of the genitalia, breast development, wider hips and public hair

58
Q

Gonadotropin releasing hormone (GnRH)

A

From the hypothalamus stimulates the pituitary to release the gonadotropins. Stimulates release of FSH and LH

59
Q

What is the role of FSH and LH in females

A

FSH stimulates the granulosa cells to secrete estrogen and LH stimulates the formation of the corpus luteum and progesterone secretion

60
Q

Labioscrotal swellings

A

Testosterone causes a pair of skin folds to grow and fuse, forming the scrotum In women they form the labia majora of the vagina

61
Q

Urethral opening

A

Where urine exits the body

62
Q

Labia minora

A

Surrounding the urethral opening is another pair of skin folds

63
Q

Where is the opening o the vagina?

A

Between the labia minora

64
Q

Endometrium

A

The inter most lining of the uterus (closest to the lumen) Role is to nourish a developing embryo and if pregnancy does not occur it is shed once a month

65
Q

Myometrium

A

Surrounds the endometrium. Thick layer of smooth muscle compromising the wall of the uterus

66
Q

Uterine tubes

A

The uterus ends here and then extends into the pelvis on either side

67
Q

Fimbriae

A

Uterine tube ends at this bunch of finger like structures

68
Q

Cervix

A

Separates vagina and uterus

69
Q

Female stages of the sexual act

A

Arousal, orgasm and resolution

70
Q

Arousal stage

A

Erection and lubrication

71
Q

Lubrication in females

A

Controlled by the parasympathetic nervous system, the clitoris and labia minora become encouraged in blood

72
Q

What is lubrication in females provided by

A

Lubrication is provided by mucus secreted by greater vestibular glands and by the vaginal epithelium

73
Q

Orgasm in the female

A

controlled by the sympathetic nervous system and involves muscle contraction

74
Q

What is different between the female sexual act and the male?

A

Females do not experience ejaculation

75
Q

Oogenesis

A

Begins prenatally. In the female ovary, germ cells divide mitotically to produce many orgo is and enter the first phase of meiosis and stops at prophase I (primary oocytes) Male mitotic division occurs in adult stage not in the womb

76
Q

1st mitotic division after puberty

A

results in a larger 2nd locution containing all the cytoplasm and organelles. Followed by a polar body (cell is haploid)

77
Q

2nd mitotic division

A

Occurs only if the primary oocyte is fertilized by sperm. Unequal division resulting in a large ovum and small 2nd polar body

78
Q

What happens if fertilization occurs?

A

The nuclei from the sperm and egg do not fuse immediately. They must wait for the secondary oocyte to release the second polar body and finish maturing to an ootid and then ovum Finally, the two nuclei fuse and the diploid (2n) zygote is formed

79
Q

Primary Oocyte

A

Not an isolated cell. Found in a clump of supporting cells called granulosa cells and the entire structure is known as a follicle

80
Q

Granulosa cells

A

Assist in maturation. Surrounds an immature primary oocyte and forms primordial follicle

81
Q

Zone pellucida

A

Oocyte itself forms a protective later of mucopolysaccharides

82
Q

Fate of the follicle

A

Insert picture

83
Q

Estrogen

A

Made and secreted by the granulosa cells (with help from the thecal cells) during the first half of the menstrual cycle

84
Q

Steroid hormones in females

A

Estrogen and Progesterone

85
Q

Progesterone

A

is involved in the hormonal regulation of the menstral cycle and pregnancy

86
Q

Stages in the ovarian cycle

A

Follicular phase, ovulatory phase, luteal phase

87
Q

Follicular phase

A

Primary follicle matures and secrets estrogen controlled by FSH

88
Q

Ovulatory phase

A

2nd oocyte is released from the ovary due to LH and what is left of the follicle becomes the corpus lutem

89
Q

Luteal phase

A

Full formation of the corpus luteum. Secrets both estrogen and progesterone

90
Q

Uterine Cycle

A

Preparation of the endometrium for potential implantation of a fertilized egg Menstruation, proliferative phase and secretory phase

91
Q

Mensturation

A

Degeneration of the corpus luteum and drop in estrogen and progesterone. The lining then sloughed out “bleeding”

92
Q

Proliferative phase

A

Follicle produces estrogen which causes production of a new endometrium LH levels peak

93
Q

Secretory phase

A

Development of endometrium increases

94
Q

GnRH from the hypothalamus

A

Stimulates the release of FSH and LH from the anterior pituitary

95
Q

What happens when estrogen reaches its threshold?

A

It’s effects on LH become positive

96
Q

Stimulation of LH

A

Causes ovulation and turns the follicle into the corpus luteum which. Secrets estrogen and progesterone and marks the start of the secretory phase

97
Q

What happens if pregnancy does not occur

A

High levels of estrogen and progesterone feedback to inhibit FSH, LH and GnRH

98
Q

What happens when LH secretions drop

A

The corpus luteum regresses and mesntration occurs

99
Q

How is ovulation prevented during pregnancy?

A

Constant high levels of estrogen and progesterone seen during pregnancy to inhibit secretion of LH by the pituitary No LH surge no ovulation

100
Q

If fertilization occurs

A

The embryo implants itself in the endometrium and the placenta begins to develop

101
Q

Chorion

A

Portion of the placenta derived from the zygote takes LH’s place and secrets HCG which maintains the corpus luteum

102
Q

When the secondary oocyte is ovulated and enters the uterine tube

A

Is it surrounded by the corona radiation and the zone pellucida. The oocyte will remain fertile for about a day. When intercourse occurs sperm becomes capacitance and survive 2-3 days to swim to the 2nd oocyte

103
Q

Sperm capacitation

A

Involved the dilution of inhibitory substances present in semen

104
Q

Fertilization

A

Occurs in the uterine tube usually. The fusion of spermatozoan with the secondary oocyte

105
Q

Acrosome

A

Large vesicles in the sperm head contains hydrolytic enzyme which are release by exocytosis.

106
Q

Once the corona radiation is penetrated

A

the acrosomal process containing actin elongates towards the zone pellucida

107
Q

Embryogenesis

A

Begins within hours of fertilization, but proceeds slowly in humans. 1st stage is cleavage: Zygote undergoes many cell divisions to produce a morula (ball of cells)

108
Q

Morula

A

Same size as the zygote: dividing cells spend most of their time in S phase and M phase they skip G1 & G2

109
Q

When division continues the morula is transformed into

A

The blastocyst through blastulation

110
Q

Tropohblast

A

Secrets protease that lyses the endometrium cells and allows the blastocyst to burrow into the endometrium and become engulfed in it. Absorbs nutrients through trophoblast into the inner cell mass Gives rise to chorion which gives rise to the placenta

111
Q

Blastocyst

A

Travels to uterus and implants a week after fertilization

112
Q

Inner cell mass

A

Will become the embryo

113
Q

Where does cleavage occur in animals?

A

In a very small portion of the yolk at the animal pole (the side of the egg with the least amount of yolk)

114
Q

Meroblastic cleavage

A

Incomplete division in animals partial part of the yolk

115
Q

What does the trophoblast secrete?

A

Protease that lyse the endometrial cells

116
Q

Secretory phase of endometrial cycle

A

Occurs so the endometrium can uptake glycogen, lipids and other nutrients

117
Q

Placenta

A

Specialized to facilitate exchange of nutrients, gases and even antibodies between the maternal and embryonic bloodstreams

118
Q

Why is hCG essential?

A

For maintenance of the endometrium In the 1st 3-months of pregnancy until placenta forms

119
Q

Placental villi

A

Chorionic projections extending into the endometrium, into which fetal capillaries will grow This surrounds sinuses which contain maternal blood

120
Q

A minion

A

Surrounds fluid-filled cavity which contains the developing embryo

121
Q

Yolk Sac

A

Important in reptiles and birds because it contains the nourishing yolk Mammals do not store yolk, our yolk sac is the 1st sire of red blood cell synthesis

122
Q

Allantois

A

Develops from the embryonic gut and forms the blood vessels of the umbilical cord, which transport blood between embryo and placenta

123
Q

Gastrulation

A

When the three primary germ layers (the ectoderm, the mesoderm and the endoderm) become distinct

124
Q

Ectoderm

A

Entire nervous system, pituitary gland (both lobes), adrenal medulla, cornea and lens, epidermis of skin and derivatives (hair, nails, sweat glands, sensory receptors), nasal, oral, anal epithelium

125
Q

Mesoderm

A

All muscle, bone and connective tissue Entire cardiovascular and lymphatic system, including blood Urogenital organs (kidneys, uterus, gonads, reproductive ducts) Dermis of skin

126
Q

Endoderm

A

GI tract epithelium (except mouth and anus) GI glands (liver, pancreas, etc) Respiratory epithelium Epithelial lining of urogenital organs and ducts Urinary Bladder

127
Q

Neurulation

A

Formation of the nervous system. Layer of the ectoderm invaginates and pinches on the back of the embryo to form the dorsal neural groove which leads to neural tube and then leads to the brain and spinal chord

128
Q

Notochord (mesodermal origin)

A

Gives instructions for neural tube formation which leads to the vertebral column

129
Q

Organogenesis

A

Development of organ systems By the 8th week all organs are present and embryo turns into the fetus

130
Q

Differentiation

A

Specialization of cell types during development. Cells become better at performing a particular task, but less adept to other tasks

131
Q

Totipotent cells

A

Primitive (stem) cells in an early embryo have the potential to become any cell types Determination comes before differentiation

132
Q

Determined

A

Point in development of a cell at which the cell fate becomes fixed

133
Q

How does determination happen

A

Determination can be preprogrammed or induced by a cells environment

134
Q

Parturition

A

Technical term for birth. Dependent on contraction of muscles in the uterine wall

135
Q

Labor contractions

A

Increased pressure on the cervix passes a threshold that makes the anterior pituitary secrete oxytocin

136
Q

Steps on birth

A

(1) Dilation of the cervix (2) Birth, involves contractions and movement of body down the cervix and birth canal (3) Expulsion of the placenta

137
Q

Result of increased levels of estrogen and progesterone secreted by the placenta during pregnancy

A

Causes further development of glandular and adipose breast tissue. These fall after parturition and allow for prolactin the be released and milk production to begin

138
Q

What happens when sucking occurs

A

The pituitary gland is stimulated by the hypothalamus to release a large surge of prolactin. Sucking prolongs secretion of prolactin and production of milk

139
Q

Oxytocin

A

Posterior pituitary hormone Necessary for milk-let down Released when suckling occurs

140
Q

Animalistic is split into

A

(1) Parazoa: animals that lack true tissue (2) Eumetazoa: radial and bilateral symmetry

141
Q

How many germ laters do radial animals have?

A

2 germ layers

142
Q

Bilateral animals have how many germ layers?

A

3

143
Q

Acelomates

A

Solid bodies; flat worms

144
Q

Coelomates

A

Fluid filled body that separates digestive tract

145
Q

Coelomates can be divided into two distinct lines of evolution

A

Protostomes: annelids, mollusks and arthropods. Mouth first Deuterostomes: echinoderms and chordates. Anus first

146
Q

What kind of cleavage do protostomes undergo?

A

Spiral, determinate cleavage, while deuterostomes undergo radial, indeterminate cleavage

147
Q

Spiral Cleavage

A

This results in smaller cells that lie in grooves between larger cells

148
Q

Radial Cleavage

A

Cells align on top of one another