BIOLOGY LECTURES 1-8

Pseudoscience

system of ideas or misconceptions, false recorded as science

Example of pseudoscience

Snake oil, smoking is good for you, climate change is fake because of ‘geoengineering’

PSA

prostate specific antigen

Sperm

male gamete found in most male animals. Head contains 23 chromosomes

Gametes

a sex cell, males = sperm, females = egg

seminiferous tubules

tiny tubes in the testes that are at the site of sperm production

Epididymis

tubes at the top of each testis that store sperm

Testes

pair of organs responsible for synthesizing sperm and making male sex hormones

Scrotum

external pouch that contains testes in many mammals

Penis

organ of the mail reproductive and urinary system

vas deferens

tubes that transport sperm from the testes to outside the body

seminal vesicles

provides nourishment and protection for sperm

bulbourethal gland

glands that produce a pre-ejaculatory fluid to lubricate and neutralize acidity in the urethra during sexual arousal, helps sperm survive

Prostate gland

a gland that produces a fluid that nourishes and protects sperm, contributing to semen, helps sperm survive

endocrine system

regulates chemical messengers called hormones. controlled by the pituitary gland in the hypothalamus of the brain

target glands

receive information from hormones to release their own target hormones

Sperm Pathway

seminiferous tubules → epididymis → vas deferens → urethra

FSH

follicle stimulation hormone, comes from pituitary to produce more testosterone and sperm

LH

Lutenizing hormone, comes from pituitary to produce more testosterone and sperm

Incorrect amount of FHS/LH

too much can enlarge testes, too little can shrink them, hormone imbalance

% of men diagnosed with prostate cancer

1 in 6 men, 17%

% of men who will die from prostate cancer

1 in 36, 3%

Prostate cancer risk factors

age, ancestry, family history, those exposed to carcinogens (farmers)

unrelated factors

vasectomies, biking, frequency

Risk in men 20-34

0%, not concern until 50

PSA Antigen test

blood test to see if there is specific protein in blood

Gleason scale

can detect stage of cancer. 2-5 low, 6-7 medium (common), 8-10 high

Radical prostatectomy

complete removal, can lead to complete loss of function

Nerve sparing prostatectomy

leaves some nerves, less risks but could leave cancer

Why do PSA levels drop after surgery?

no prostate means no PSA to detect

Radiation beam

radiation to kill cancer, less side effects but can also kill good tissues

Radioactive seed

implanted into area to kill cancer, can also kill good tissues

Prostate cancer 5 year survival rate

98%

HRT

hormone replacement therapy

Reproduction

characteristics of all living things where existing creates something new

Sexual reproduction

requires genetic material from both male and female to reproduce

asexual reproduction

exact copy of parent’s DNA, bacteria

sexual dimorphism

physical differences between male and female members of the same species

genitalia

visible structures of the sexual reproductive system

labia

2 folds that cover the clitoris, urethra, and vagina

clitoris

sensitive structure in female reproductive system

vagina

tubular part of the female reproductive system that connects to the uterus

Cervix

opening to the uterus, separates the uterus from the vagina

Uterus

organ that nourishes the embryo, also called the womb

ovaries

pair of organs that release eggs and make female sex hormones

oviduct

also called fallopian tubes, brings eggs from ovaries to uterus

endometrium

layers of uterus that thicken and shed during cycle

Puberty

rapid growth and production of sex hormones

menopause

no more sex hormones to cause the shedding of the endometrium

menstruation

period, vaginal bleeding to mark the start of the menstrual cycle

menstrual cycle

cyclical build up and shedding of the endometrium, about 28 days long

ovulation

release of an oocyte (egg)

oocyte

immature eggs that have not gone through meiosis

follicle

group of cells that surround oocyte

fertilization

single sperm and oocyte share genetic code

ovum

fertilized oocyte, mature female gamete

zygote

product of fertilization

Path of ovulation (unfertilized egg)

follicle passes down oviduct → passes through uterus → passes through vagina

why has women’s cycle gotten younger?

improved nutrition, more body fat, less psychological stress, less environmental/endocrine disrupting factors

Surge in LH leads to

ovulation

drop in progesterone leads to

menstruation

corpus lutem

left over site in the follicle of the ovary after ovulation, makes progesterone if fertilized

If egg is fertilized…

implants in endometrium → more estrogen and progesterone is created

if egg is unfertilized…

No implantation → no hormonal message sent → no estrogen and progesterone created → menses

Pill

combo of estrogen & progesterone, creates negative feedback to prevent LH hormone which stops ovulation

menopause

estrogen production declines in the early 40s

perimenopause

early menopause, lasts about 5 years before menopause

early menopause symptoms

hot flashes, insomnia, dry skin, brittle hair, skipped periods

osteoporosis

bone thinning, less dense bones in menopause, can lead to fractures

Benefits of HRT in women in their 50s

reduce in cardiovascular disease and breast cancer

How long is HRT safe?

if taken at start of menopause, it is safe up to 5 years

abstinence

avoiding sex, only 100% effective form of birth control

contraception

birth control, prevents fertilization and therefore prevents pregnancy

hormone implantation

form of contraception where tubes that release hormones go under the skin. hormones stop ovulation

Intrauterine devices (IUDs)

‘T’ shaped device that goes into the uterus to prevent fertilization and a zygote from implanting

pills

combination of hormones that prevents ovulation. nearly 100% effective if taken correctly

condoms

tube to catch sperm, can be ineffective but the only birth control method that can prevent STIs

Tubal ligation

surgery form of birth control where oviduct tubes are cut/blocked preventing ovulation oocyte from being fertilized & reaching the uterus for implantation

vasectomy

surgery for men that cuts/blocks vas deferent to keep sperm from leaving the testes

plan b

emergency contraception taken within 72 hours. prevents ovulation or prevents implantation of embryo

sex

male or female is assigned at birth based on genitals and chromosomes

XX Chromosomes

female

XY Chromosomes

male

intersex

chromosomes and sexual anatomy don’t fit typical definitions

ambiguous anatomy

sex organs and genitals don’t match up, different sex organs

only X chromosome

turner syndrome

XXY chromosome

klinefelter syndrome

XXX chromosomes

trisomy x syndrome

How many people worldwide are intersex

1.44 million - 136 million (0.018% - 1.7%)

4 sexual response phases

excitement → plateau → orgasm → resolution

Cyclic GMP

activated based on nerve transmission to produce erection, the good guy

PDE5

breaks down cyclic GMP and decreases blood flow, the bad guy

Plan B

misnomer

abortion pill

blocks the action of progesterone

viruse STI

HIV, Hepatitis, HPV, Herpes

Cure for viruse STI

no cure! only can treat symptoms

Bacteria STI

Gonorrhea, Syphilis, Chlamydia

Bacteria STI Cure

Antibiotics

infertility

inability of sexually reproducing naturally. can be result of improperly formed gametes, hormone imbalance, or other physical defect.

assisted reproductive techniques (ART)

broad term for various artificial methods used to create pregnancy. can include medications or in vitro fertilization