Bio 1104 Exam 3

pathogens

disease causing organisms

• viruses and bacteria as well as some eukaryotic pathogens (malaria, tapeworm etc)

microbes

microscopic organisms

bacteria

single celled prokaryotic organisms

• most of the cells in your body are bacteria

• many bacteria are beneficial

• no membrane bound organelles, yet do have structures like ribosomes as they aren’t bound by membranes

plasmids

small circular DNA in bacteria, separate from chromosome in the nucleoid region

bacteria cell wall composition

carbohydrate and protein molecules

binary fission

the process by which bacteria reproduce

1. chromosome copied

2. attached to different parts of the cell wall as cell stretches

3. cell continues to grow, plasma membrane cinches in the middle

4. cells separate into two genetically identical daughter cells

toxins

poisonous substance produced by bacteria or other cells

anitbiotics

routinely used to treat bacterial infections, yet many disease causing bacteria have evolved to become resistant

DPT vaccine

D: diphtheria, a respiratory disease

P: pertussis, whooping cough

T: tetanus

viruses

nucleic acid (DNA or RNA) surrounded by a protein coat

• not considered to be alive, cannot replicate w/o a host cell and are not composed of cells

• cannot metabolize, have no ribosomes with which to make proteins

• do not produce proteins

retroviruses

RNA viruses w/ enzyme reverse transcriptase which synthesizes DNA from RNA

Capsid

protein coat surrounding a virus

• many animal-infecting viruses have an additional structure called the viral envelope, which is covered in surface proteins

latent viruses

enter a state of dormancy within the body

ex: herpes

encephalitis

swelling/inflammation of the brain

herd immunity

the indirect protection of the unvaccinated that occurs when the majority of community members are vaccinated

three lines of immune defense

1. skin/integumentary system

2. phagocytes and macrophages

3. lymphocytes

phagocytes

a white blood cell that indiscriminately attacks invaders and engulfs them

macrophages

a type of phagocyte that moves through the lymphatic fluid

• clean up dead/damaged cells

• secrete enzymes that break apart invaders

• release chemicals stimulating the production of more white blood cells

phagocytosis

the process of engulfing dead/damaged cells

natural killer cells

additional white blood cells that circulate through the blood stream

• attack invaders without being activated by the immune system

inflammatory response

reaction to tissue injury in which histamines are released to increase the size of blood vessels (and therefore blood flow) to the area

histamines

chemicals released by mast cells

interferons

proteins released by virus-infected cells to help other cells resist infection

complement system

part of the immune system that enhances phagocytes ability to fight infection

• defensive proteins coat the surface of microbes

• complement proteins poke holes in membranes surrounding microbes

lymphocytes

white blood cell making up the third line of immune defense

• specific

• transported by blood, the lymphatic system, or by moving though spaces between cells and tissues

antigens

structures on the surface of pathogens that trigger a specific immune response

B Cells and T Cells

lymphocytes whos production increases when antigens are present

• move through the circulatory and lymphatic systems

• concentrated in the spleen and lymph nodes

antigen receptors

protein on B and T cells that bind to certain antigens

(act as antibodies when separate from B or T cells)

passive immunity

short term immunity when antibodies are passed from one individual to another

ex: a mother breastfeeding

active immunity

immunity when an individual creates their own antibodies

allergy

immune response when no pathogen is present

autoimmune disease

disease resulting from the body’s immune system attacking normal body cells

antibodies

proteins that bind to and inactivate antigens

endocrine system

internal system of regulation of hormones, the glands that secrete them, and the cells that respond to them

hormones

chemicals that travel through the circulatory system and act as signals to elicit a response in targeted cells

• either bind to the surface of the cell or diffuse through the membrane to bind within

signal transduction

when a signal must be relayed through a series of proteins from the outside of the cell in. Occurs when a hormone cannot cross the cell membrane and must bind to outside receptors

ex: protein hormones

steroid hormones

fat soluble hormones that diffuse across the cell membrane and bind inside, causing the cell to turn specific genes on and off

sex hormones

steroid hormones most involved in producing anatomical sex differences

endocrine glands

groups of cells or organs that secrete hormones

general endocrine organs:

• thyroid

• parathyroid

• thymus

• pancreas

sex endocrine organs

• hypothalamus

• pituitary gland

• adrenal gland

• ovaries/testes (gonads)

hypothalamus

deep in the brain; regulates hunger, thirst, and reproduction

secretes gonadotropin-releasing hormone (GnRH) which triggers the pituitary gland to secrete growth hormones

pituitary gland

secretes growth hormones follicle stimulating hormone (FSH) and luteinizing hormone (LH)

gonadotropin-releasing hormone (GnRH)

hormone secreted by the hypothalamus, triggers the pituitary gland to release FSH and LH

follicle stimulating hormone (FSH)

males → sperm production

females → egg development

luteinizing hormone (LH)

males → testosterone production

females → egg release during ovulation

adrenal gland

sits atop the kidneys, secretes adrenaline as well as a small amount of both sex hormones

androgen

a masculinizing hormone

axial skeleton

supports the trunk of the body, consists of the bones making up the spine and the skull

appendicular skeleton

bones making up the hip, shoulder and limbs

calcium

used to remodel the skeleton

osteoblasts

bone forming cells that deposit collagen

osteoclasts

bone reabsorbing cells that liberate calcium

osteoporosis

the weakening of bone resulting from bone reabsorbtion outpacing bone deposition

primary hormone involved in bone remodeling

estrogen

myofibrils

parallel arrays of thin actin filaments and thick myosin filaments found within muscle cells

• made up of sarcomeres separated by Z-discs

antagonistic muscle pairs

pairing where one muscle is paired with one of the opposite effect (biceps and triceps)

leptin

hormones that signals to the brain that a woman’s body fat is too low to sustain a pregnancy, which stops the menstrual cycle

toxic stress

prolonged activation of the stress response which can have long term physical and mental effects

endometrium

lining of the uterus which is shed during menstruation

follicle

developing egg surrounded by hormone-secreting cells

first half of the menstrual cycle

• follicle grows and produces estrogen

• estrogen stimulates GnRH release, spiking FSH and LH levels for approximately 24 hours

• LH peak trigger ovulation 12 hours later, around two weeks before your period

second half of the menstrual cycle

• after ovulation what remains of the follicle is called the corpus luteum

• the corpus luteum produces progesterone and estrogen

progesterone

an ovarian hormone that promotes blood flow to the uterus during early fetal development. inhibits LH production in a negative feedback loop

corticotropin-releasing hormone (CRH)

hormone released by the hypothalamus in response to stress

triggers cortisol

zona pellucida

protective layer over the egg

acrosome

enzyme on the tip of the sperm that creates a tunnel through the zona pellucida, fusing the egg and sperms plasma membranes together

zygote

fertilized egg cell

cleavage

rapid cell division of the zygote in the oviduct

morula

result of the rapid cell division during cleavage, ball of cells

blastocyte

hollow ball of cells developed from the morila over the next days

buries itself in the uterine lining in a process called implantation

trophoblasts

cells in the blastocyte that create enzymes for implantation

human chorionic gonadotropin (hCG)

hormone triggered by implantation

extends the life of the corpus luteum

gestational age

stages of pregnancy measured from the first day of woman’s last period

gastrula

structure of the embryo developed after around three weeks

composed of three layers that will differentiate into specific adult cells and tissues:

• ectoderm: top layer that will form the brain, nervous system, skin and sense organs

• mesoderm: forms the muscles, gonads, skeleton, excretory organs, and primitive circulatory system

• endoderm: becomes a tube lined with mucus membranes, within which the lungs, bladder and intestines will develop

congenital abnormalities

defects present from birth

teratogens

environmental factors resulting in congenital abnormalities

fetus

the embryo once all the organs and limbs are in place (about nine weeks after fertilization)

prolactin

hormone that stimulates the mammary glands for milk production

oxytocin

hormone that stimulates contractions during labor and milk production when breastfeeding

• positive feedback during labor, triggers contractions which triggers the release of more oxytocin, gradually intensifying contractions

stages of birth

1. cervix dilates to around 10cm, baby is pushed against cervical opening

2. a mother’s active pushing expels the baby through the narrow pelvic opening and birth canal

3. delivery of the placenta ends positive oxytocin feedback loop