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Flashcards in REPRODUCTION and immunity Deck (303):
0

asexual

process in which a single cell or set of cells produces offspring that inherit all of their genetic material from one parent

1

scrotum

sac that houses the testes outside the abdomen

2

sexual

process in which genetic material from two parents combines and produces offspring that differ genetically from either parent

3

spermatozoa (sperm)

the mature motile male sex cell of an animal, by which the ovum is fertilized, typically having a compact head and one or more long flagella for swimming

4

epididymis

Long, thin coiled tube where sperm mature and are stored

5

prostate gland

I gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid

6

testosterone

A steroid hormone that stimulates development of male secondary sexual characteristics, produced mainly in the testes, but also in the ovaries and adrenal cortex

7

steroid

any of a large class of organic compounds with a characteristic molecular structure containing four rings of carbon

8

acrosome

holds enzymes in a sperm

9

urethra

the tube in the penis for both semen and urine

10

three glands that make semen

seminal vesicle
cowpers
prostate

11

the structure in testes that makes sperm

seminiferous tubule

12

where is the egg typically fertilized?

in the fallopian tube

13

what closes off the uterus and dilates when a woman is in labor

cervix

14

which cells nurture the egg?

follicle

15

what does FSH tell the ovary to make

follicle

16

layer that becomes muscle and bones

mesoderm

17

A neurological gland that releases growth hormone

pituitary gland

18

outer layer of blastocyst

trophoblast

19

endometrium

where blastocyst embeds

20

types of pathogens

fungus, virus, bacteria, Protozoa

21

pathogen fungus examples

athletes foot, yeast infection

22

virus pathogen examples

HIV, herpes, chickenpox, swine flu

23

bacteria pathogen examples

tuberculosis, E. Coli, strep throat, leprosy

24

protazoa

malaria, amoebic dysentery

25

prions

infectious proteins

26

a "big eater" that works by phagocytosis

macrophage

27

lymphatic system

A part of the circulatory system that collects fluids and blood

28

what starts puberty

release of hormones

29

how oftem do eggs mature?

every 28 days
one at a time in alternate ovaries

30

menstrual cycle

rhythmic and maturation of eggs and other chemical and physical events that accompany the process

31

how is the menstrual cycle controlled

by chemical messengers (hormones) that move via the bloodstream

32

hormones

chemical messengers that move via the bloodstream

33

follicle stimulating hormone (FSH)

hormone that when high enough in levels start the maturing process of the eggs in a woman's ovary

34

where does each egg mature?

inside of a follicle

35

follicle

cluster of protect cells, near the surface f one of the eggs

36

when the egg is fully mature, which hormone reaches its peak?

LH (Luteinizing Hormone)

37

when does the follicle burst open and release the egg?

when LH and FSH reach high levels

38

ovulation

when the follicle bursts open and releases the egg

39

what sweeps the egg into the tube which leads to the uterus

cilia

40

as a reaction to increasing levels of what hormone, the lining of the uterus (also called the endometrium) has been prepared to receive a fertilized egg by building it's lining with nurturing tissues and blood vessels

estrogen

41

when does the remaining follicle tissue become a hormone secreting gland (corpus luteum)

after the egg is released from the follicle in the ovary

42

which glad releases the hormone progesterone?

corpus luteum

43

high levels of which hormones help maintain the uterus wall lining as it is built up and thickened

progesterone and estrogen

44

what happens if the released egg remains unfertilized?

it does not implant in the uterus lining. This triggers further hormonal changes. Both estrogen levels and progesterone levels drop. This causes the lining of the uterus (also called the endometrium) to deteriorate. As a result, both unfertilized egg and uterus lining shed and are passed out of the body

45

periodic loss of tissues and fluid from the uterus

menstruation

46

why do females often break out in pimples before menstruation?

because the skin and estrogen are responding to estrogen

47

why don't bones respond to estrogen?

only target cells with the right receptors respond to the hormone estrogen. You do not have receptor for estrogen on bone cells

48

pituitary gland

located at the base of the brain. Secretes the two hormones that trigger the growth and development of the the egg in the Overy (FSH and LH)
in response, the ovary then secretes the two sex hormones that control development of the egg in the uterus lining (estrogen and progesterone) when ovarian hormones reach low levels, this stimulates the pituitary gland to once again secrete it's hormones to trigger the next cycle

49

the female gamete

ova/egg

50

group of cells that protect the egg

follicle

51

female gonad

ovary

52

leftover follicle that makes progesterone

corpus luteum

53

causes the formation of the corpus luteum

leutenizing hormone

54

works with estrogen to thicken the endometrium

progesterone

55

on what day does the FSH reach its peak in concentration

13-14

56

what day does LH reach its peak in concentration?

14

57

what happens to the egg on day 14 after LH reaches its peak

The follicle bursts open and releases a fully developed egg and during a process known as ovulation

58

what gland secretes estrogen?

ovary

59

on what day does estrogen reach its peak in concentration?

12-13

60

why does the female need a steak uterus lining if fertilization does occur?

thick lining will catch and support the developing embryo

61

what makes menstruation cycle?

hypothalamus restarts process when hormones are low

62

first line of nonspecific chemical body defenses

sweat
oil
mucus
acid

63

first line of nonspecific physical body defenses

shedding epidermis
cell membrane

64

"moat"

sweat
oil
mucus

65

"wall"

physical barriers

66

second line of nonspecific body defenses

Macrophage (guard)
(Swelling) Histamine (alarm)

67

humoral response

b cells that attack using antibodies (CIA)

68

cell mediated response

cytotoxic t cells that attack by popping

69

first trimester time period

1-12 weeks

70

at what week will the srY gene either turn on or stay off?

8 weeks

71

which hormone stars contractions?

oxytocin

72

parasite

uses host organelles for energy and to make offspring

73

retro viral infection

insert genetic information which embeds with in the host genes, eventually destroying host

74

gamates

human sex cells

75

how are human sex cells made?

meiosis

76

purpose of semen

fluid that raises the pH to above seven to neutralize the vagina, produces sugar first sperm to eat, lubricant, for sperm to swim

77

muscular tube that propels the spermatozoa towards the urethra

vas deferense

78

three glands that make semen

seminal vesicle
cowpers
prostate

79

monthly steps for females

one. The pituitary hormones LH and FSH are released into the blood
two. An ovum starts to develop a follicle which produces estrogen so the uterine lining gets thick
three. at day 14 ovulation occurs
four. follicle becomes the corpus luteum, which makes progesterone
five. the corpus luteum dies so the uterine lining is uneeded and us shed in a process called menstruation
six. the egg doest meet a soerm in the fallopian, so it dissolves
seven. another ovum starts to develop in one of the ovaries and the process begins again

80

hypothalamus

detects low hormone levels triggers master gland

81

gastrulation

infolding of blastocyst forming germ layers
1. endoderm
2. mesoderm
3. ectoderm

82

functions of blood

transporting oxygen, water and nutrients to cells.
distributes hormones throughout body
removes waste products
fight infection and heal wounds

83

leukocytes

white blood cells
have a nuclei and mitochondria
responsible for fighting infection/ preventing growth of cancer

84

pathogens

disease causing organisms or viruses

85

types of pathogens

certain bacteria
protozoans
fungi
worms
viruses

86

infectious diseases

diseases that are caused by pathogens

87

disease

I just order of structure or function in a human, animal or plant especially one that produces specific signs are sometimes

88

germ theory of disease

infectious disease is caused by pathogens that can spread the disease from one organism to another organism

89

how pathogens are transmitted

inhaling
physical contact
contaminated food or water
sexual contact
animals

90

ideal location for the virus to invade cells and multiply

mucous membrane

91

nonspecific defenses

does not distinguish one invader from another

92

epidermis

outer layer of skin that is comprised of tough, dead cells that most bacteria and other organisms cannot penetrate. constantly shedding so bacteria cannot embed and grow

93

lysozome

found in saliva and tears. an enzyme that breaks down the cell walls of many bacteria

94

digestive and respiratory system

lined with mucous membranes (barrier)
mucus in the trachea creates a sticky barrier the traps microorganisms. Silly on movies trapped particles up to the pharynx where there swallowed. Then, stomach acids and enzymes help to destroy the pathogens, as well as many other of microorganisms and your food and drink

95

what happens if pathogen evade the first line of body defenses

met with second line: internal nonspecific defenses
includes certain pathogen destroying white blood cells, the inflammatory response, and certain specialized proteins. Since they do not single out specific pathogen, these defenses are also said to be nonspecific, like the first line of differences

96

macrophage

destroys microorganisms through phagocytosis
when it encounters invading pathogen, it engulfs it. enzymes like lysozymes kill the pathogen

97

neutrophils

smaller and more numerous than macrophages.
kill by phagocytosis.

98

at three weeks the embryo has three layers that make up the embryonic disk. Which layer will become the muscles and bones?

mesoderm

99

what hormone causes the egg and follicle to mature?

FSH
Follicle Stimulating Hormone

100

what hormone is produced by the corpus luteum?

progesterone

101

FSH in the male causes the production of...

spermatozoa

102

which hormone is responsible for fraternal twins?

FSH
follicle stimulating hormone

103

what hormone will an embryo send to the corpus luteum to ensure that it continues progesterone production?

LH

104

at eight weeks, testosterone floods the fetus and turns it into a

male
xy

105

after implantation, the developing human is called an

embryo

106

the lungs, and the digestive and reproductive systems result from the...

endoderm

107

mitosis stages after interphase:

prophase
metaphase
anaphase
telephase

108

The stage of mitosis where the chromosomes appear in the nuclear membrane breaks down

prophase

109

where must sperm pass when going from the vagina to the uterus

cervix

110

contains the eggs
produce estrogen and testosterone

ovary

111

crater like structure that produces progesterone and estrogen

corpus luteum

112

a membrane found at the opening of the vagina

hymen

113

This part of the sperm contains an enzyme that can dissolve the egg coating

acrosome

114

this gland provides a protective coating that counteracts vaginal acids

prostate

115

provides food (fructose) for the sperm

seminal vesicle

116

this is where sperm is manufactured in the testicles

seminiferous tubules

117

where sperm is stored. It is attached directly to the testes

epididymis

118

The bursting of the follicle and the formation of the corpus luteum is controlled by

LH

119

what does luteinizing hormone from the pituitary gland cause to bd produced in males

testosterone

120

what does follicle-stimulating hormone from the pituitary gland caused be produced in the male body

sperm

121

a mature egg cell

ovum

122

endometrium

inner uterine lining

123

difference between fallopian tube and oviduct

no difference
oviduct is the medical term

124

what do male pituitary glands release?

LH and FSH
testes release testosterone after puberty
never release progesterone

125

pituitary releases..

LH and FSH
triggers the ovary to release estrogen
after day 14 the corpus luteum releases the estrogen

126

what triggers the white blood cells response to attack

recognizing foreign molecules

127

Natural Killer (NK)

type of white blood cell
they recognized body cells that have become infected by a virus and kill them by releasing chemicals that poke holes in the infected cells membrane. Natural killer cells also recognize and attack abnormal body cells such as cancer cells. They played a key role in defending against cancer by killing abnormal cells before they can form a tumor

128

inflammatory response

A nonspecific defense characterized by redness, heat, swelling, and pain.

129

mast cells

cells that release a type of chemical alarm called histamine at the site of pathogen invasion

130

histamine

A chemical secreted by mast cells which causes nearby blood vessels to dilate. The expanded blood vessels increase the volume of blood flowing to the injured tissue. In addition, the vessels become more porous, allowing more blood plasma to leak into the interstitial fluid.

131

dilate

expand

132

interstitial fluid

A solution that famous and surrounds the cell of multicellular animals. It is the main component of the extracellular fluid, which also includes plasma entry and cellular fluid.

133

what happens during an inflammatory response

during an inflammatory response, chemical signals trigger changes in blood vessels and attract white blood cells that help destroy the invaders

134

phagocyte

A type of cell within the body capable of engulfing and absorbing bacteria another small cells and particles

135

what produces the redness, heat, swelling and pain you may experience around the injured area

The local increase of bloodflow, fluid, and white blood cells

136

what is the major function of the inflammatory response

removing pathogens and cleaning injured tissues. Inflammation may occur in a tiny area, such as the site of a mosquito bite. Or, if pathogens get into the body or release toxins that are carried throughout the body by the circulatory system, the whole body may react with an inflammatory response. In such a response white blood cells increased and a fever may occur

137

why is a high fever dangerous

because it can destroy proteins and cause other damage. But a moderate fever may contribute to the defense by stimulating phagocytosis and stopping the growth of many kinds of microorganisms

138

interferon

A family of proteins produced by cells in response to becoming infected by a virus. the infected cell may die, but it's interferon reaches healthy cells in the area, stimulating them to produce proteins that interfere with virus reproduction. affected against many viruses so it is nonspecific. affective against flu and common cold

139

antiviral proteins

proteins that are introduced about human or animal cells to interfere with viral replication

140

name two major functions of the immune system

sdestroy pathogens and detect and kill abnormal cells

141

which type of pathogen is always intracellular

viruses

142

examples of surface barriers

skin, mucus membranes

143

examples of innate internal defenses

cells and chemicals in body fluids

144

adaptive defenses (specific)

t and b cells

145

after the surface barriers a.k.a. any external defenses are penetrated, what is the next line of defense?

me (nonspecific) internal defenses

146

name the four keyways adaptive defenses differ from innate defenses

are specific, they involve BNT lymphocytes, they have memory, and they can act anywhere in the body

147

specific b cells called plasma cells secrete antibodies which bind to the

antigens

148

what is the first line of defense in lungs?

mucus in the nasal cavity traps foreign particles before they can enter the lungs

149

scribe how macrophages protect the human body

macrophages engulfed any pathogens that have passed the physical barriers. engulfing process is called phagocytosis

150

how do B cells recognize a specific virus? What do they do with the virus after they recognize it?

each of these cells have a different receptor protein on the surface of the used to attach to a particular virus. When he sounds fine to the virus than golfing and then break it into pieces to display pieces on the outside to alert helper T cells. Eventually these cells become antibody producing factories

151

b cells produce y shaped proteins called

antobodies

152

Albertise cells will use chemical signals called

cytokines
trigger infected b cells to multiply

153

what is the purpose of a memory cell

The memory cell will rapidly produce the virus/antigen when they encounter the virus during the second infection. This is why you never get really sick with that virus again

154

The kind of blood cells that play a role in the body's immune system

white

155

A substance for into the body, such as disease causing organisms, that stimulates the body's immune system

antigen

156

A protein substance produced by the body to fight and invading foreign substance such as a disease causing organisms

antibody

157

immune system T cells developed in this gland

thymus

158

a chemical produced by the body that protects against viruses

interferon

159

The immune system can cause this response following an organ transplant

rejection

160

lymphocyte

A specific white blood cell that is involved in antibody production

161

The process by which a white blood cell ingests a disease causing organisms

phagocytosis

162

what does AIDS stand for

acquired Immune Deficiency Syndrome

163

what does HIV stand for?

human immunodeficiency virus

164

disease characterized by a breakdown of the body's immune system

AIDS

165

A substance injected into the body that helps protect against disease

vaccine

166

The type of immunization that is long-lasting

active

167

the type of immunity that is short term

passive

168

the type of disease in which the immune system itself attacks the body

autoimmune

169

lymphocyte that alerts when the body is invaded

helper t cell

170

cells that release ntobodies

plasma cells

171

turn into plasma cells

B lymphocytes

172

they poke holes in infected cells

Cytotoxic or killer T cells

173

third line of defense

immune system

174

The immune system

third line of defense. this system recognizes and defense against specific pathogens, cancer cells, and certain chemicals. specific/targeted defense.

175

immunity

when the body is resistant to the pathogenx that causes a specific disease.

176

how is immunity acquired

by becoming infected by the pathogen

177

antigen

A large molecule, usually a protein, that provokes an immune response.
antibody generating

178

antobodies

proteins found on the surface of certain white blood cells, or in blood plasma, that attach to particular antigens

179

most common antibody shape

y shape

180

what is at the tip of each arm of the Y

antigen binding site, or antigen receptor

181

what does the shape of the binding site make it possible for the antibody to do

for the anti-body to recognize a specific antigen with a complementary shape. each antigen sits on the surface of the invading particle and has a particular shape but knobs that protrudes from the surface

182

markers

unique to each antigen

183

explain how a specific antibody can bind to a specific antigen

just as a particular key is shaping able to fit into a specific lock, the antigen marker fits into a specific antibody. There is a huge variety in the three-dimensional shapes of antigen binding sites. This variety gives antibodies the ability to recognize an equally large variety of antigens

184

how are antigens neutralized

an anti-body tags the invader by binding to the antigen molecule. This triggers mechanisms that neutralize or destroy the invader

185

what does binding to an antigen do

The binding of antibodies stops and viruses from attaching to a host cell. This disables the virus and halts further infection.

186

antigens cause pathogens to clump together. What does this clumping do

this clumping makes the cells easy targets for phagocytes to capture and destroy

187

complement ptoteins

antibodies me also activates immune system chemicals called complement proteins that can attach to viral services or bacterial membranes. These proteins help to call viruses for fish is a Texas by white blood cells are puncture holes in bacterial outer membranes, causing the pathogen to break open. All of these antibiotic mechanisms involving specific recognition and attack phase, followed by nonspecific destruction phase

188

lymphocytes

The white blood cells that recognize specific invaders

189

where do lymphocytes originate

in bone marrow from stem cells

190

b cells (b lymphocytes)

A white blood cell that continues their development in bone marrow.

191

T Cells or T Lymphocytes

transported to the thymus gland where they mature

192

where do both B cells and T cells eventually travel to

in the blood to the lymph nodes and other parts of the lymphatic system

193

what enables things to target particular antigens

The ability to target particular antigen is due to the specific shapes of the antigen receptors on the lymphocyte surface

194

B cells play a key role in

humoral immunity

195

he sells played a major role in

cell mediated immunity

196

helper t cell mission

to coordinate immune system attacked by a recruiter sheeting and activating other immune system cells

197

when ejaculation occurs during sexual intercourse, the sperm enters where

the vas deferens

198

what do B cells defend primarily against

bacteria and viruses that are found outside of cells in body fluids

199

what activates a B cell

when fighting a pathogen, a B cell containing the matching androgen receptor binds to the antigenic the pathogen. activation means that the B cell grows and clones itself, forming millions of identical cells. Each of the cells is capable of developing into a plasma cell

200

plasma cell

A cell that produces and secretes antibodies specific to the antigen that activated the original b cell

201

humoral immunity

Community that originates from the cells

202

how do t cells work

T cells work by directly attacking hosts that contain multiplying bacteria or viruses. these host cells are actually body cells that have become infected

203

how do T cells recognize infected cells?

each T-cell has receptors for a specific antigen. When a pathogen infects a body cell, the pathogens antigens are displayed on the surface of the body cell

204

cytotoxic T cells

T cell clones which is then attack cells infected with the pathogen that triggered the response. Cytotoxic T cells binding to an infected cells membrane and poke holes in it by secreting a protein called perforin
The infected so leaks fluid, breaks open, and dies

205

what happens during the humoral response

b cells produce antibodies after being activated by free antigens present in body fluids

206

what happens during a cell mediated response

cytotoxic t cells attack infected cells that display the antigens of pathogens on their surface

207

helper t cell

both you moral and cell mediated immunity gets a boost from a particular type of lymphocyte called helper T cells. Like all lymphocytes, helper T cells are present in many versions, each with surface receptors that recognizes specific antigen. Like cytotoxic T cells, the helper T cells activated by finding to sells the display antigens of a pathogen. But the antigen displaying sell that helper T cells recognize her macrophages, the white blood cell that you pathogens bifacial sentences.

208

how do helper T cells respond to this announcement

by secreting chemicals that activate both cytotoxic T cells and B cells

209

cell mediated immunity

attack on infected cells

210

humoral immunity

secretion of antibodies by plasma cells

211

long lasting lymphocytes

memory cells

212

primary immune response

The first formation of B and T cells to battle new invading pathogen. this first response is relatively slow and we can because time is needed for enough specific lymphocytes to form to detect the pathogen

213

secondary immune response

A second exposure to the same pathogen triggers a much quicker and stronger response

214

The second exposure stimulates the memory B cells to rapidly produce plasma cells double secrete antibodies specific to that antigen. Meanwhile memories cells a.k.a. T cells rapidly produce large numbers of cytotoxic T cells that attack cells infected with the pathogen. The process is so quick but you don't develop symptoms of the disease. Your body destroys the invader before you feel sick

swaq

215

Dr. Jonas Salk

polio vaccine

216

vaccine

A dose of a pathogen or part of a pathogen that is been disabled or destroyed so it is no longer harmful

217

booster shot

this shot is an additional dose of an antigen that boosts antibody production and extends the memory for that antigen

218

why are booster shots important

because some of the initial memory cells that were produced after the first shot died

219

active immunity

whenever your body produces antibodies against infection. can develop from catching a disease such as chickenpox or from receiving a vaccine, such as that for polio.

220

passive immunity

when your body receives antibodies for a particular disease from another source

221

allergy

an abnormal oversensitivity to an otherwise non-harmful antigen which is called an allergen

222

antihistamine

A drug that blocks the action of histamine, minimizing symptoms of an allergic reaction

223

anaphylactic shock

dangerous type of allergic reaction

224

autoimmune disease

The immune system turns against some of the bodies own molecules

225

what happens when HIV destroys the body's helper T cells

The immune system cannot activate other T cells or B cells. Both the Hume oral and cell mediated immune responses are impaired, and the body cannot fight pathogens.

226

an organism that causes an infectious disease is called

pathogen

227

where are eggs produced

ovary

228

uterus

hollow, muscular organ with thick walls, roughly the size and shape of a pear

229

neck of the uterus

cervix

230

connects the uterus to the vagina

cervix

231

vagina

flexible, thin walled organ about 9 cm long

232

functions of the vagina

receives the penis and spermatozoa during intercourse
birth canal through which the baby exits
passage way for menstrual flow

233

the main male reproductive structures

testes
scrotum
epididymis
vas deferens
penis

234

where do sperm begin development

testes

235

singular of testes

testis

236

function of the scrotum

house the testes outside the main body cavity to keep them cool

237

semen

The substance that is emitted during the process called ejaculation

238

ejaculation

muscular contractions propel spermatozoa from the epididymis through the connecting ducts called the vas deferens and finally through the urethra

239

ejaculation takes place muscles at the base of the urethra contract and close off the outlet from the

bladder

240

penis

and organ consisting mainly of specialized tissues called erectile tissue. filling of this tissue with blood causes an erection

241

through what process are sex cells generated

meiosis

242

when does the development of the egg cells begin

before a female is born

243

primary oocyte

a diploid cell that is in the prophase stage of meiosis 1. at this stage the process pauses

244

secondary oocyte

egg/ova

245

ovum

mature egg cell with a haploid nucleus that is capable of fusing with a spermatozoa

246

primary spermatocyte

the beginning process of spermatozoa synthesis

247

where do spermatozoa complete development

epididymis

248

ovarian cycle

refers to the cyclic changes that occur in the ovaries

249

menstrual cycle

refers to the cyclic changes that take place in the uterus

250

first part of the ovarian cycle

follicular phase

251

what triggers the hypothalamus to secrete a releasing hormone, which causes the anterior pituitary to secrete follicle-stimulating hormone and lutenizing hormone

low estrogen levels

252

as the follicle matures, what does it secrete

estrogen

253

hypothalamus

A region of the forebrain below that Salamis that cord needs both the autonomic nervous system and the activity of the pituitary

254

what do rising levels of LH signal in males

signal the testes to produce and secrete testosterone

255

what stimulates spermatozoa production

the combination of FSH and testosterone

256

the master control center of that endocrine system

hypothalamus

257

prolactin

stimulates milk production
anterior lobe

258

Fertilization

occurs when the egg and sperm cells fuse

259

zygote

fertilized sex cell

260

what does successful fertilization require

living sperm in the oviduct on the day of, or shortly after, ovulation.

261

function of the acrosome

contains enzymes that help the spermatozoa cells penetrate the protective coats of the oocyte

262

50/50 chance

chance of entering the wrong oviduct the one that doesn't contain the egg

263

what prevents more than one sperm from entering

once one sperm successfully contracts the plasma membrane of the oversight, a barrier forms on the oocytes surface that prevents other sperm from entering. This ensures that just one sperm nucleus will be present to fuse with the ovums nucleus

264

mid piece

contains mitochondria

265

developing human (after 9 weeks)

embryo

266

implantation

The embedding of the blastocyst in the second endometrium that lines the uterus

267

The function of a trophoblast

The trophoblast grows, extending into the endometrium and anchoring the blastocyst in place. The trophoblast contributes to the development of the membranes that will nourish and protect the embryo. The intercell mass will eventually form the organism itself

268

The result of more than one egg being fertilized during an ovarian cycle. For this to happen, both ovaries must release an egg, or one ovary must release two eggs

fraternal twins

269

why are fraternal twins genetically different

each zygote fraternal twins is formed from a different egg and sperm. As a result, the genetic information for fraternal twins is different for each individual, and the same way that brothers and sisters born at different times have different genetic material.

270

The result of one early stage embryos splitting into two

identical twins

271

what does the embryo consist of at implantation

The trophoblast and an inner cell mass

272

where do stems cells come from

The intercell mass gradually gives rise to the organs and tissues of the embryo. Cells of this inner mass are also called stem cells

273

gastrulation

approximately three weeks after fertilization, a process called gastrulation takes place. Gastrulation forms three cell layers: ectoderm, endoderm and mesoderm

274

three layers of gastrulation

ectoderm, endoderm and mesoderm

275

ectoderm

outer layer
forms the outer part of the embryo skin and the central nervous system

276

endoderm

inner layer
forms the digestive track and lungs

277

mesdoderm

middle layer
forms most of the other organs

278

amnion

A membrane that forms a fluid filled sac
protects the embryo from physical impact

279

yolk sac membrane

produces the first blood cells and is the source of cells that eventually form gametes

280

chorion

A third membrane that becomes the embryos portion of the placenta

281

what forms part of the umbilical cord that connects the embryo to the placenta

allantois

282

placenta

soon after implantation, trophoblast cells and cells from the uterus form an important structure called the placenta. The placenta develops inside the uterus and surrounds the embryo. This structure enables nutrients and waste products to be transferred between the mother and developing baby

283

by when is the placenta fully formed and functional

the third month

284

fetus

from week 9 to birth
name of developing human

285

fetal position

when the fetus is filling up much of the space in the uterus and it curls forward

286

24 until birth

third trimester

287

why is it important for pregnant mothers to be nutritious

during pregnancy, substances and the mothers bloodstream are transferred to the fetus is bloodstream, this is how the fetus is nourished for nine months. But this transfer process can pose a serious health risk for the fetus is the mother doesn't have a healthy lifestyle.

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labor

A series of strong arrhythmic contractions of the muscles of the mother's uterus

289

lymphocyte

eventually become B cells (bone marrow) go to blood stream slash lymphatic system
or T cells (thymus)

white blood cells

290

nonspecific defense mechanism

first line of defense
second line of defense

291

spleen

part of lymphatic system that helps filter waste that the lymph finds. located mid abdomen area

292

amniotic sac

sac in which the fetus develops

293

tonsils

part of the lymphatic system in the throat

294

HCG

human chorionic gonadotropin
produced in the pituitary gland
levels raise when pregnant

295

t cell vs helper t cell

helper t cell would activate the cytotoxic t cells

296

capsid

outer layer that incloses the virus
protein coat

297

cleavage

when a cell pinches to split into two

298

gonads

ovary and testes

299

lytic

make more viral protein

300

trophoblast becomes...

placenta
umbilical chord
amniotic sac

301

blastocyst becomes..

embryo

(endo meso ecto)

302

lytic vs lyso

lytic - virus attaches, inserts, tricks to make new, continues to make new in body
lyso - attaches, inserts, hides in nucleus, comes out, hides again