Reproduction and Homeostasis Flashcards

Flashcards covering reproduction, homeostasis, and related concepts from lecture notes.

Reproduction

Generating more members of own species

Sexual reproduction

Two different sex cells (haploid cells - meiosis) from 2 different individuals fusing together to reproduce 1st cell (diploid cell) of new organism

Asexual reproduction

1 parent produces offspring genetically identical to parent (mitosis)

Meiosis

Breaks up parental combinations of alleles and creates genetic diversity

Fusion of gametes

Produces new allele combinations via fusion of male and female gametes (fertilization)

Sperm

Male gamete; motility to travel to female; smaller size; less food reserves; more numbers produced

Egg

Female gamete; sessile (immobile); larger size; more food reserves; fewer numbers produced

Testis

Produces sperm and testosterone

Scrotum

Holds testes at a lower than core body temperature

Epididymis

Stores sperm until ejaculation

Sperm duct

Transfers sperm during ejaculation

Seminal vesicle and prostate gland

Secrete fluid containing alkali, proteins and fructose that is added to sperm to make semen

Urethra

Transfers semen during ejaculation and urine during urination

Penis

Penetrates the vagina for ejaculation of semen near the cervix

Ovary

Produces eggs, oestradiol and progesterone

Oviduct

Collects eggs at ovulation, provides a site for fertilization then moves the embryo to the uterus

Uterus

Provides for the needs of the embryo and then foetus during pregnancy

Cervix

Protects the foetus during pregnancy and then dilates to provide a birth canal

Vagina

Stimulates penis to cause ejaculation and provides a birth canal

Vulva

Protects internal parts of the female reproductive system

Menstrual cycle

Recurring changes occurring in female reproductive system to make pregnancy possible

Ovarian cycle

Series of hormonal & physiological changes that occur in ovaries. Maturation & release of egg (ovum) from ovary

Uterine cycle

Changes occurring in endometrium (lining of uterus) in response to hormonal fluctuations

FSH (Follicle Stimulating Hormone)

Stimulates follicular growth and Stimulates estrogen (oestradiol) secretion (from developing follicles)

LH (Luteinizing Hormone)

Surge causes ovulation and Formation of corpus luteum

Estrogen (oestradiol)

Thickens & repairs uterine lining and Inhibits FSH & LH most of cycle but Stimulates FSH & LH release pre-ovulation

Progesterone

Thickens uterine lining and Inhibits FSH & LH

Follicle

Fluid filled sac with immature egg cell

Corpus luteum

Walls of ruptured follicle develop into temporary mass of cells

Negative feedback

Increased level of 1 hormone inhibits secretion of other hormones

Positive feedback

Rise in level of one hormone causes increase in levels of other hormones

Fertilization

Fusion of sperm and egg to form diploid zygote

Thermotaxis

Change swimming direction towards warmer temp

Chemotaxis

Sperm moves due to chemical gradient

In vivo

Natural method of fertilization in humans (occurs inside the living tissues of the body)

In vitro fertilization

Occurs outside body in controlled lab conditions

Hermaphrodite

Flowers that have male & female parts

Anther

Pollen producing organ of the flower (pollen is plant sperm)

Filament

Slender stalk supporting the anther

Stigma

Sticky tip of the pistil; responsible for catching pollen

Style

Tube-shaped connection between the stigma & ovule

Ovary

Hold female gametes (ovules) & develop into seed after fertilization

Pollination

Transfer of pollen from male anther to female stigma

Fertilization (plants)

Sperm (in pollen tube) fuses with egg, in ovule (in ovary of carpel)

Seed dispersal

Movement of seed away from parent plant

Pollen tube

Produced after pollen lands on stigma of a carpel

Dioecy

Individual plants are male or female (self-pollination is not possible!)

Protandry & Protogyny

Flower's male & female parts mature at different times

Heterostyly

Different lengths of stamens & pistils within same species

Self-incompatibility

Genetic mechanism preventing self-fertilization (promotes cross-pollination)

Inbreeding depression

Decline in vitality, fertility & resistance to stress as a result from lack of genetic diversity

Germination

Development & growth of plant embryo into seedling

Homeostasis

Tendency for organism or cell to maintain constant internal environment within tolerance limits

Positive feedback

Increases the gap between the original and new level

Negative feedback

Decreases the gap, so original level is restored

Insulin & Glucagon

Secreted from pancreatic pits (islets of Langerhans) and act on liver

Beta (β) cells

Secretes insulin into bloodstream when blood glucose levels increase (after eating)

Alpha (𝝰) cells

Secretes glucagon into bloodstream when blood glucose levels decrease (during exercise)

Diabetes

Consistently elevated blood glucose levels even during prolonged fasting

Type 1 Diabetes

Autoimmune, Beta cells damaged and body no longer produces insulin

Type 2 Diabetes

Beta cells produce insulin, but liver and muscle cells do not respond to insulin; Target cells resistant to insulin

Thermoregulation

Physiological processes warm-blooded animals (homeotherms) maintain stable core body temperature

Thyroxin

Increases basal metabolic rate of body and Leads to production of heat

Vasoconstriction

Vessels constrict and Less blood flow to the surface of skin thereby Less heat loss

Vasodilation

Vessels dilate and bring more blood to surface so heat lost from the blood

Hair Erection (Piloerection)

Muscles in skin contract, Pull hair shafts upright & erect thereby Upright hair traps air (acts as insulator - preventing heat loss)

Brown adipose tissue (BAT)

Specialized adipose (fat) tissue with lots of mitochondria

Uncoupled respiration

Involves aerobic respiration producing heat - not ATP