Final Flashcards
(122 cards)
1
Q
Types of Asexual Reproduction
A
- Binary Fission- amoeba, bacteria, ecoli
- Budding- yeast
- Spore Formation- fungi
- Fragmentation- flatworms (annelids)
- Vegetative Reproduction
- Parthenogenesis (virgin birth)- some reptiles
2
Q
Advantages of Asexual Reproduction
A
- Efficient
- Don’t need to spend time finding a mate
- All organisms can reproduce
3
Q
Disadvantages of Asexual Reproduction
A
- Lack of Genetic Diversity
- All organism respond same way to the environment
- Organisms lack the ability to adapt to changing environment
4
Q
“Two fold cost of sex” Hypothesis
A
Only one half of the population is suitable to give birth, the other half is useless
5
Q
Advantages of Sexual Reproduction
A
- Creates Genetic Diversity
- Genetic Variation: gives at least some members of a population an opportunity to survive a deadly disease or adverse scenario
- DNA repair: removing DNA damage by recombinational DNA repair during meiosis
6
Q
Red Queen Hypothesis
A
It takes all the running you can do to keep in the same places which means that a population as a whole needs to continuously adapt to keep up with conditions and parasites
7
Q
Origin of Sexual Reproduction
A
Protoeukaryote- Last eukaryotic common ancestor (LECA)
8
Q
Basis of Sexual Reproduction (Meiosis) entails..
A
- Alteration of Ploidy
- Origination of Gametes
- Mating type regulated transmission of organelle genomes
9
Q
Alteration of Ploidy
A
Increase in genome size and ploidy: more information to work with , increase in the genome size favors experimentation- allows for positive selection and accumulation of favorable mutations- allows for positive selection and accumulation of favorable mutations
10
Q
Origin of the Gametes
A
Anisogametes (different gametes) and the recognition of “self” vs. “non self” is one of the key reasons for the origin of eukaryotic sex
11
Q
Regulation of Organelle Genomes
A
Organelles such as mitochondria are only inherited from one sex. The rational is that the fusion of gametes would generate diploid zygotes with twice the organelle-genome tally- this guards against “heteroplasmy”, the presence of two or more different organelle genomes in the same organism
12
Q
Types of Reproductive Processes: Oviparous
A
Female lay eggs which hatch outside the body (birds, fish)
13
Q
Types of Reproductive Processes: Ovoviparous
A
Give birth to live young which hatch from eggs inside the body (snakes, lizards, and amphibians)
14
Q
Types of Reproductive Processes: Viviparous
A
Give birth to live young which are nourished by contact between placenta and uterus (mammals)
15
Q
Mammalian Reproduction Variations
A
- Induced vs Spontaneous Ovulation
- Delayed Fertilization (out of hibernation)
- Delayed Implantation (Embryonic diapause), (bears, seals, small carnivores, seals and sea lions), males and females often separate while foraging, copulation occurs when both sexes together on land during birth period: two types- obligate, facultative
- Spontaneous Abortion (Bruce Effect): the tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male
- Monozygotic Polyembryony
- Environmental control of gestation length
- Menopause
- Intrafollicular Fertilization
16
Q
Endocrine Glands
A
Directly released into blood stream or lymph, ductless
ex. anterior pituitary
17
Q
Exocrine Glands
A
Secretes many types of substances; have ducts; sweat, oil, wax, enzymes
ex. endometrial secretion of uterine milk
18
Q
Paracrine Cell Hormone Communication
A
Hormone stimulates adjacent cells without entering the blood- releasing hormones
19
Q
Autocrine Cell Hormone Communication
A
Hormone stimulates the same cell that secretes the hormone
20
Q
Juxtacrine Cell Hormone Communication
A
Hormone stimulates the cell in contact- notch signaling
21
Q
Intracrine Cell Hormone Communication
A
Hormone acts within the cell- steroid hormones
22
Q
Classification of Hormones
A
- Source of origin
- Target Tissues
- Mode of action
- Biochemical Classification
23
Q
Origin of:
Hypothalamus-
Pituitary-
A
- neuronal
- neuronal and endodermal
24
Q
Terminology: Hypothalamus- Pituitary- Posterior Lobe of Pituitary- Anterior Lobe of Pituitary- Pituitary Stalk-
A
- Diencephalon
- Hypophysis
- Neurohypophysis, pars nervosa
- Adenohypophysis, pars distalis
- infundibulum, pars tuberalis
25
Connection between Anterior and Posterior
Pituitary has distinct nuclei that ends in the posterior.
| Portal system- two capillary systems that are connected
26
Function of the hypothalamus
Regulates homeostasis, in reproduction its the regulator of the pituitary gland
27
Relationship between hypothalamus and pituitary
For every hormone released by the pituitary, there is a corresponding releasing hormone in the hypothalamus
28
Classification of GnRH
- made by the hypothalamus
| - acts on the anterior pituitary
29
Classification of FSH/LH
-made by the anterior pituitary
-acts on the gonads
-control of reproductive function
LH- stimulates progesterone, FSH-stimulates growth hormones
30
Classification of Oxytocin
- made by hypothalamus
- stored by posterior pituitary
- acts on the ovary and testis for uterine contractions and to stimulate milk ejection
31
Classification of Prolactin
- made in the anterior pituitary
- targets the mammary gland
- milk production
32
Different types of neurohormones
Releasing, gonadotropins, sexual promotion, pregnancy maintenance, parturition, luteolysis
33
Example of releasing hormone
GnRH
34
Example of Gonadotropins
FSH, LH
35
Example of Sexual promotion and secondary sex characteristic hormones
estradiol, testosterone
36
Example of pregnancy maintenance hormone
progesterone, placental lactogen
37
Example of parturition hormones
oxytocin, relaxin
38
Example of a luteolysis hormone
PGF2a
39
What is a neurohormone
a hormone that is produced and released by neurons
40
Structures of hormones
- peptides- produced by hypothalamus, 11 amino acids, small
- glycoproteins- produced by pituitary
- steroid
- prostaglandin
41
What does structure say about function or origin of hormones
if produced by the hypothalamus then they are small peptides, if produced by the pituitary then they are glycoproteins
42
Role of GnRH
Promotes the release of FSH and LH at appropriate times in both sexes
43
What is GnRH stimulated by?
Estrogen ( surge center), Leptin
44
What is GnRH inhibited by?
- progesterone, testosterone, and estrogen (tonic center)
- estrogen inhibits GnRH release in the tonic center and stimulates it in the surge center
- estrogen in rapid pulses suppresses the tonic center
45
Effects of Oxytocin in the female
- Targets myometrium and endometrium, increases uterine tone
- promotes uterine PGF2a synthesis
- Milk let down
- Stimulates maternal behavior and bonding
46
Effects of Oxytocin in the male
- pre-ejaculatory movement spermatozoa in epidimal tail, ductus deferens, and ampulla
- Promotes PGF2a synthesis
47
Glycoproteins
-FSH, LH
- made of carbohydrate and protein: means they are antigenic and will degrade
- structure has 2 subunits: alpha which is different for each species and Beta which is unique for each hormone but the same in every species
(alpha tells you which species you are beta tells you which hormone you are)
48
FSH (Follicle Stimulating Hormone)
- Gonadotropin
- synthesized in the anterior pituitary
- glycoprotein
- targests gonands
49
Functions of FSH in the female
- follicle growth
- stimulates support cells called "granulosa cells" : estrogen synthesis and release, some progesterone synthesis and release, inhibin synthesis and release, follistatin synthesis and release
50
Functions of FSH in the male
- initiates spermatogenesis
- stimulates support cells called "sertoli cells" : inhibin synthesis and release , androgen binding protein synthesis and release, some estrogen synthesis and release
51
Leutinizing Hormone (LH)
- gonadotropin
- glycoprotein
- synthesized in the anterior pituitary
52
Functions of LH in the female
- ovulation: oocyte maturation, follicle rupture
| - corpus luteum formation and function: progesterone synthesis and release
53
Functions of LH in the male
-Stimulates leydig cells: testosterone synthesis and release, maintains spermatogenesis
54
Gonadal Hormones
- Steroid hormones such as estradiol, progesterone, testosterone
- all have cholesterol basis
- lipophillic and thus able to cross cell membranes directly and bind to steroid receptor in the nucleus activating transcription of target cells
55
Estradiol (E2)
- steroid hormone
| - produced by granulosa cells and placenta in the female and the sertoli cells in the male
56
Effects of Estradiol in the female
- estrus behavior
- elevated secretory activity of entire female tract
- enhanced uterine motility
- growth and duct development in mammary glands
- growth of female reproductive tract
57
Effects of Estradiol in the male
- sexual behavior (role in development)
| - helps to maintain normal spermatogenesis
58
Progesterone (P4)
- hormone of pregnancy
- steroid hormone
- made by the corpus luteum and placenta
- increases endometrial secretion
- decreases uterine tone
- inhibits release of GnRH through negative feedback
- inhibits reproductive behaviors
- promotes pregnancy: component of birth control
59
Testosterone
- steroid hormone
| - synthesized in leydig cells (male) and theca cells (female)
60
Effects of Testosterone in the male
- masculinization
- spermatogenesis
- secretion in accessory sex glands
- anabolic growth
- libido, aggressive behavior
61
Effects of Testosterone in the female
- substrate for granulosa cells to synthesize estrogen
| - in excess can cause abnormal masculinization
62
Prostaglandins
-derived from cell membrane phospholipids
63
Prostaglandin F2a
- modified fatty acid from arachadonic acid pathway
| - made by the endometrium (female) and vesicular glands (male)
64
Effects of PGF2a in the female
- promotes luteolysis
- increases uterine tone and contractions
- promotes ovulation
65
Effects of PGF2a in the male
- epididymal contractions
| - influences metabolic activity of spermatozoa
66
How do hormones function?
- requires presence of receptor in target tissue
- protein hormones utilize membrane bound receptors
- steroid hormones diffuse into cells and attach to specific intracellular receptors
67
How do prostaglandins signal?
-through cell-surface receptors similar to protein hormones
68
Relationship between hormones and glands
Endocrine glands produce hormones and releases them into the bloodstream, mostly as a result of inductive signals
69
Features of Reproductive hormones
- act in minute quantities
- have short half lives
- bind to specific receptors
- regulate intracellular biochemical reactions
70
What dictates a half life?
- protein hormones, water soluble hormones, FSH/LH,insulin have short half lives
- eCG and hCG have longer half lives
- chemical alterations can increase half-life
71
The functions of the male reproductive system
- exocrine: produce sperm
- endocrine: testosterone
- help spermatozoa reach its ultimate goal
72
Three types of somatic cells in testes
- Sertoli: branch like and surrounded by germ cells, essential for testicular development, most important, dictates sperm production capacity, provides structural support for germ cells, dictates how many germ cells will have for a species and that will determine its size
- Germ cell
- Leydig: makes testosterone
73
Epidiymis
- composed of a long convoluted tube that connects the efferent ductules of the testis with the ductus deferens
- houses the sperm as they reach maturity and become motile
74
Spermatogenesis
sperm production
75
Maturation of Sperm
- sperm leaving the testis and entering the epididymis are non motile and not capable of fertilization
- sperm acquire motility and final maturation as they travel through the epidiymis
76
Vas Deferens
- continuation of the tail
- muscular tube composed mainly of smooth muscle
- undergoes peristaltic contraction during ejaculation, propelling sperm from the epididymis to the urethra
77
Seminiferous Tubules
-sperm production
78
Rete Testis
- concentrating sperm
79
Efferent Ducts
- fluid absorption
80
Epidiymis
-sperm maturation and storage
81
Vas Deferens
-transport of sperm
82
Spermatic cord
- consists of vessels, nerves, lymphatics, and the ductus deferens
- suspends each individual testis within the scrotum
83
Urethra
- tube that extends from the bladder through the penis to the outside of the body
- carries urine and semen
- composed of heterogeneous segments: prostatic, membranous, and spongy
84
Penis
- external male organ
- enlarged structure on the end of the penis is the glans penis
- covered by foreskin
- made of spongy, erectile tissue
- functions: urination, erection
85
Path that spermatozoa travel
Seminiferous tubules, rete testes, epididymis, vas deferens, urethra, penis
86
Scrotum
- supporting structure for testes
- scrotal septum- internally divides scrotum into two sacs, each with a single testis
- manages temperature
87
Descent of Testis
- in fetus the gonads develop in the sublumbar region immediately caudal to the kidney
- the testes descend sometime after birth to the scrotum as the lower temperature is favorable for spermatogenesis
- descent occurs in the inguinal canal
88
Cryptorchidism
- the testis that fails to descend into the scrotum is called cryptorchid
- if both remain in abdomen then likely to be steril
- an unilateral cryptorchid is fertile as long as the one testis produces normal spermatozoa
- associated with infertility and tumors
89
Accessory Reproductive Glands
the male accessory sex glands produce the bulk of the ejaculate or semen, the medium for transport of sperm
90
Ampullary Glands
- paired glands
- found lying on dorsal neck of bladder
- connected to the urethra via the ejaculatory duct
91
Vesicular Glands
- paired glands
- found dorsalcranial to the pelvic urethra
- in boar and bull they produce large proportion of the overall volume ejaculate
- in boar and bull these have irregular surface but in stallion they are smooth
92
Prostate Gland
-singular gland
-found at junction of the bladder and urethra
-variation between species: heart shaped in the boar, h shaped in the stallion, and four lobes in the tom
Two parts:
corpus prostate- a compact body of tissue that is found in the stallion and dog and cat and bull
disseminate prostate- a diffuse tissue found in the ram and boar
93
What affects sperm production
- size of testes
- scrotal circumference
- size of cauda epididymis
- cryptorchidism
- effect of ejaculation
94
Avian Male Reproductive System
-consist of paired testes, epididymis, vas deferens
-testes do not descend
- no spermatic cord, vaginal tunic, scrotum, urethra, or accessory reproductive glands
-testes are large and white during breeding season
-epididymis is not divided
-sperm is stored in vas deferens and diluted with lymph fluid and ejaculated as a mixture during copulation
ducts of the testes lead to the vas deferens which carry sperm from the testes to the papillae in the cloaca
95
Functions of the female reproductive tract
- produce viable oocytes
- maintain environment for growth and development of fetus
- serve as copulation receptacle
- produce hormones necessary for reproduction
96
Female Reproductive tract consists of
ovaries, oviducts, uterus, cervix, vagina, external genitalia, broad ligament
97
Functions of the ovary
- produce oocytes
- produce hormones: estrogen and progesterone
- the ovarian cortex houses the oocytes
98
Follicle
- houses the maturing oocytes
- made up of theca and granulosa cells and later a fluid-filled antrum
- grows in stages: primary, secondary, tertiary, graafian
99
Corpus Luteum
- formed after ovulation of follicle
- preceeded by corpus hemorrhagicum
- essential for maintenance of pregnancy
100
Corpus Albicans
- form from the CL in various stages of degeneration from previous cycles
- appears orange at first, then white and scar like
101
Ovary
- in most species the ovarian cortex is on the outside and the medulla is on the inside and ovulation occurs randomly throughout the ovary
- in the mare the ovarian cortex is on the inside and the medulla is on the outside and ovulation occurs at one site on the ovarian fossa
102
Oviduct
- secretes substances necessary for sperm survival
- may provide substances which aid in fertilizing ability of sperm
- three sections are the infundibulum, ampulla, and isthmus
103
Infundibulum
- surrounds ovary at time of ovulation
- captures the ovulate oocyte
- covered with fimbrae
104
Ampulla
- greater then or equal to half of oviductal length
- large diameter
- site of fertilization
105
Isthmus
- smaller diameter
| - directly connected to uterus via UTJ
106
Uterotubal Junction
- in cows it regulates the movement of embryo into the uterus , estradiol creates a kink and progesterone straightens the kink
- in pigs constriction serves as barrier to sperm transport and prevents sperm from reaching ampulla
107
Functions of the uterus
- sperm transport
- luteolysis and control of cyclicity
- environment for preattachment embryo
- maternal contribution to the palcenta
- expulsion of fetus and placenta
108
Uterus types
simplex, duplex, bicornuate
109
Type of uterus is determined by
- number of cervices
| - uterine horn structure
110
Bicornuate Uterus
- large horns
| - seen in cow, mare, sow, doe, ewe
111
Duplex Uterus
- two cervices
| - opossum , rabbit
112
Simplex Uterus
- one cervix, no uterine horns
| - primates
113
3 Uterine Layers
- perimetrium: serosal layer, thin
- myometrium: muscle layer
- endometrium
114
Functions of the Uterus Endometrium
- secretions important for survival of embryo
| - secretions change in response to hormone levels
115
Uterine Surface
Ruminants: Caruncles
| Mare and Sow: Endometrial Folds
116
Cervix
- thick organ contains a lumen with folds or rings
- ruminants: finger like projections
- sow: interdigitating rings:semen deposited here
- mare: cervical folds
- secretes mucus for lubrication of vagina and flushing
- during pregnancy, mucus becomes viscous
- cervical seal of pregnancy
117
Functions of Vagina
- copulatory organ
- birth canal
- expulsion of urine
118
Vagina
- cow and mare: cervix protrudes into the vagina creating a pocket (fornix vagina)
- suburethral diverticulum- a problem for AI in cows and sows
119
Vulva
- external genitalia
| - two labia (major and minor)
120
Clitoris
- female homologue of penis
- contains many nerve endings
- stimulation can increase AI conception rate
121
Summary of Sex Determination
- initially gonads are bipotential(meaning that under appropriate cues they can form ovary or testis)
- formation of testicular supporting cells called sertoli cells is the key "sex determination event" in males
- if the sertoli cells fail to form, ovary will be the end result
122
Two key events in sex determination
- formation and migration of 'germ cells' to the gonad
| - specification of supporting cells to sertoli cells (or granulosa cells) to jump start gonadogenesis
