Lab #7 Animal Hormone Systems

Testosterone negative feedback pathway

Hypothalamus --> GnRH + --> Anterior Pituitary --> LH + --> Testes --> Testosterone

Thyroid hormone negative feedback pathway

Hypothalamus --> TRH + --> Anterior Pituitary --> TSH + --> Thyroid Gland --> Thyroid Hormone

Cortisol negative feedback pathway

Hypothalamus --> CRH --> Anterior Pituitary --> ACTH --> Adrenal Gland --> Cortisol

Pineal gland hormones

Melatonin

Pituitary gland hormones

ACTH, LH

Thyroid Gland hormones

Thyroxine

Thymus hormones

Thymosin

Adrenal gland hormones

Cortisol

Pancreas hormones

Insulin, Glucagon

Ovaries hormones

Estrogen, progesterone

Testis hormones

Testosterone

Hypothalamus

Pituitary gland

Hypothalamus Tissue

Pineal gland

Thyroid gland

Thymus

Adrenal glands

Pancreas

Ovaries

Testis

Anterior pituitary gland tissue

2

Posterior pituitary gland tissue

1

Interstitial cells

Seminiferous tubules

Seminiferous tubules function

Produce, maintain, and store sperm

Testis Developing sperm

2-5

What is the main anatomical difference between the anterior and posterior pituitary glands?

Posterior: projection of the brain --> stores and releases hormones into circulation

Anterior: Independent body --> Produces and releases its own hormone

What is the functional connection between the interstitial cells and the developing sperm cells in the testis?

Interstitial cells produce testosterone in the presence of LH which maintains spermatogenesis

Chronic stress can results in very high levels of cortisol. The hypothalamus and anterior pituitary stop responding to these levels of cortisol through negative feedback, and as a result cortisol levels can stay high. Explain the effect this might have on the strength of the immune response in chronically stressed animals

Suppresses immune system and inflammatory pathways making the body more susceptible to disease

Some bodybuilders abuse anabolic steroids like testosterone. What effects would this have on the size of the testes?

Decrease in size due to negative feedback

Effect of increased TRH

Enlarged Pituitary,
enlarged Thyroid

Decreased body weight

Effect of increased TSH

Small Pituitary

Enlarged Thyroid

Increased body weight

Effect of increased ACTH

Small Pituitary

Enlarged Adrenal glands

Decreased body weight

Effect of increased Cortisol

Small Pituitary,

small Adrenal glands

Decreased body weight

Effect of increased testosterone with intact testis

Small Pituitary,

small testes

Enlarged Prostate,

enlarged Seminal vesicles

Increased body weight

Effect of increased LH with intact Testis

Small Pituitary

Enlarged Prostate,

enlarged Seminal vesicles,

enlarged testes

Increased body weight

Activity 3 Table

100% Correct