ANS 2 Final 1/3 material up to Midterm 2

Dr Teixeia

Why do animals perform a behavior?

climate, habitat, other animals, food

What is behavior considered?

flexible and dynamic response, can change quickly

Why do animals need to perform behaviors?

survival and fitness

What is this indicative of?: animals with higher __ pass on genetic material to next generation

fitness

Parts of fitness

survival, reproduction; find food, shelter, and avoid being killed, find mates, provide for young

What is behavior driven by?

survival and fitness

Definition of fitness:

the ability for an animal to survive based on offspring

Proximate question

asks “how”; over a lifespan; hormones brain function, protein synthesis

Ultimate question

asks “why”; over generations; survival and fitness

manual castration

physically removing the testicles to reduce aggression and improve meat quality

What will be lost as a result of castration?

the development of testosterone and sperm

How does immunocastration work?

involves a vaccine that induces antibodies against gonadotropin-releasing hormone; interrupts reproductive hormone production

Why would one immuno-castrate?

reduces aggression and unwanted pregnancies while improving meat quality and animal welfare. reversible procedure

What happens if GnRH is cut off?

the lutenizing hormone/ follicle stimulating hormone will not be moved to the testis and they will not produce testosterone or sperm

What types of maternal behaviors will a female exhibit(generally)?

nesting, responsiveness, discrimination

Types of young?

precocial and altruicial

precocial young

stand soon after birth, can hear, see etc.

Altricial

dependent on mother, often blind, no fur/wool/hair

Why is reproductive biology important?

food/meat quality, offspring, good parents for efficient offspring

Where is sperm made?

in the testes

Where is sperm matured?

in the epididymis

Where does the sperm go after being matured in the epididymus?

expelled into and out the vas deferens

Where can sperm be stored temporarily in animals with a short ejaculation time?

the ampulla

Where do sperm start the process of becoming semen? Why?

the ampulla; glands add fluids like nutrients, medium to move in

Where do sperm go after the ampulla?(or vas deferens in animals that don’t have an ampulla) What is added here?

seminal vesicle; nutrients for sperm

Where does the sperm/ semen go after the seminal vesicle and what does this add to the sperm?

prostate; adds fluids for motility

Where does the sperm/semen go after the prostate? What does this structure do?

the bulbourethral gland(cowper’s gland); flushes urethra of anything acidic so it doesn’t kill sperm

When is sperm considered semen?

after it has gone through all three accessory glands

Why might an animal have testicles that drop away from the body?

to reduce the amount of heat on the sperm; sperm is killed if too high a temperature

What structure do pigs have that is enlarged compared to other animals? What is the purpose?

pigs have a large bulbourethral gland which produces a more gelatanous semen

Where do boars ejaculate into in the female sow?

the cervix

Where do bulls ejaculate into in a cow?

the vagina

What animal does not have accessory glands?

chickens!

Where does spermatogenesis occur in the testes?

the retetestes

What does the spermatic chord do?

hold testes to body

Where are leydig and sertoli cells located?

in and around seminiferous tubules

Are leydig cells in or around the seminiferous tubules?

around in the interstitial tissue

Are sertoli cells in or around the seminiferous tubules?

in the seminiferous tubules

Metaphorically, what are sertoli cells?

bubble wrap for the sperm

What will the body do if the sperm escape into the interstitial tissue?

it will cause an immune response killing off the sperm

In the seminiferous tubules, do sperm get more mature toward the inside or outside of the tube?

as they approach the lumen (inside)

What does the scrotum do?

support testicles and regulates temp of testes

Where is spermatozoa and testosterone produced int he testicles?

in the interstitial cells

Where are hormones released into?

the blood and are carried to other parts of the body to produce specific regulatory effects

Where do hormones work?

only in the cells they are designed for

What is the hypothalmic-pituitary gonal axis? How does it opperate?

neuroendocrine system, regulates reproduction, development, and sex hormone levels; operates via cascade

How are the sex hormones activated?

the hypothalmus released GnRH, stimulating the anterior pituitary to secrete LH and FSH, which promp the gonads to produce sex steroids

Where are hormones produced?

in the endocrine system

What does the hypothalamus link?

the nervous system and endocrine system and regulates body processes

What is this an example of?: nervous system has a stimulus and reacts→hpothalamus makes a decision of what to excrete→ the pituitary secretes hormone

the cascade effect of the hypothalamic-pituitary-gonadal axis

What do somatotrope cells produce?

growth hormone(GH)

What do corticotrope cells produce?

adrenocorticotropic hormone(ACTH)

What do thyrotrope cells produce?

thyroid stimulating hormone(TSH)

What do lactotrope cells produce?

prolactin(PRL)

What do gonadotrope cells produce?

gonadotropins (LH, FSH)

What does follicle stimulating hormone do?

stimulates sertoli cells in testis; induces growth of follicles in ovary

What does lutenizing hormone do?

stimulates testosterone production by leydig cells in the testis; stimulates estrogen production in ovary and ovulation

What will happen if the body has too much testosterone?

it will not release other hormones because the system is “shut down”

What is hormonal control regulated by?

feedback systems

What is the most common type of feedback system?(negative or posititve)

negative- body produces a hormone until it reaches a threshold and decreases the release

How does a negative feedback system work?

uses the product of a process to decrease its own production; maintains appropriate physiological levels of hormones

What hormone builds sertoli cells?

follicle stimulating hormone

WHat hormone builds leydig cells?

lutenizing hormone

What cell, leydig or sertoli, secrete testosterone that will evenutally “shut off” the system?

leydig cells

WHere does spermatogenesis occur?

in the seminiferous tubules

List the order of how sperm develops within the seminiferous tubules.

spermatogonium→primary spermatocyte(meiosis 1→)seconfary spermatocyte(meiosis 2→) spermatids

What are spermatids?

sperm that develop into sperm that will try to go to an egg

Wha

What part of the sperm contains DNA(nucleus)?

the head

What does the sperm head have on it that helps it penetrate the egg?

enzymes

What is the sperm tail made up of?

midpiece+principal piece+end piece

What part of the sperm provides energy for motion?

the midpiece

WHat is spermatogenesis?

the process of differentiation from diploid spermatogonia (germ cell) to haploid spermatozoa (gamate)

How is the hormonal regulation of spermatogenesis regulated?

in a negative feedback system where the end-product down-regulates the original stimulus

True or false:spermatogenesis involves mitotic and meiotic divisions, and morphological transformations

true

What is mitosis?

a division of a cell that produces two identical body cells for growth and tissue repair

What is meiosis?

a process that produces four genetically unique sex cells (gamates) for sexual reproduction

What does testosterone do to a male animal?(physically and behaviorally)

more muscle, less fat, increased aggression

What is the membrane that the sperm has to penetrate called?

zona pellicida

What is a zygote?

the initial cell formed when a sperm fertilizes and egg

What is an ovary, what does it do?

the location of eggs in the female reproductive tract; where hormones are produced

What is the infindibulum and where is it?

it is a “vacuum” that sits around the ovary to “catch” an egg during ovulation

What occurs in the oviduct?

where fertilization occurs

What is the uterus? Where does the fetus grow in most animals?

the uterus is the canal to the uterine horns; generally, fetus is grown in the uterine horns

What is the cervix?

it is used as an identifier for where to inseminate, sperm can be held here in a cryp which is a reservoir within the cervix

What does the vagina do?

it ensures pH is correct and clean

Where is the urinary bladder and why is its location important?

it is below the reproductive tract and it helps with preventing infection

What is the vulva?

external structure, opening from outside to the vagina

Where does fertilization occur in birds?

in the infindibulum

What occurs in the magnum?

the albumin is created

What occurs in the isthmus?

the shell membrane is developed

What occurs in the shell glad?

the shell is developed

Do birds have a vagina?

yes and a cloaca which is the outermost part

What is the function of the ovary?

egg production; estrogen and progesterone production

What does the infundibulum do?

guides egg to oviduct

What does the oviduct do?

site of fermentation(except in birds)

What does the uterus do?

site of fetal development(more specifically the uterine horns)

What is the barrier between the uterus and external envionment?

cervix

What is the copulatory organ, birth canal?

the vagina