Endocrine System Lecture

Lecture Objectives for Endocrine System

functions of the endocrine system

regulates long term processes (growth, development, reproduction), controls plasma homeostasis, and uses chemical messengers to relay information and instructions between cells

define hormone

chemical messengers that travel through blood to target cells throughout body

three types of hormones

amine, peptides, steroids

how does endocrine signaling work?

hormones disbursed through blood. hormone binds to receptors on target cells. only cells with receptors for hormone are affected but hormone travels to every cell.

amine hormone

come from amino acids (subunit of protein)

where do peptide hormones come from?

come from small proteins

what do steroids come from?

come from cholesterol

amine/peptide characteristics

free hormone secretion, short lifespan, fixed receptor model

steroid hormone characteristics

cholesterol, transport protein-bound secretion, longer lifespan, mobile receptor model

what is free hormone secretion?

hormone comes from gland and travels to blood stream

what is transport protein-bound secretion

hormone comes from gland and is protected by proteins when traveling to bloodstream

what are fixed receptor characteristics?

peptide/amines, receptor anchored to plasma membrane surface

what are mobile receptor characteristics?

steroid, receptor found inside the cell, lipid-soluble hormone diffuses

how does fixed receptor model work?

uses G protein to activate 2nd messenger. hormone binds to receptor, receptor activates G protein, G protein activates enzyme, enzyme activates 2nd messenger which delivers hormone to whole cell.

how does the mobile receptor model work?

steroid diffuses through plasma membrane and binds to receptor, receptor-hormone complex enters nucleus, binds to specific DNA region, initiates transcription of gene to mRNA, mRNA directs protein synthesis

positive vs negative feedback system

negative feedback: does opposite of stimulus

ex) when you are hot, your body sweats to cool down

positive feedback: enhances original stimulus

ex) more oxytocin during childbirth

endocrine system vs nervous system

endocrine: long term, hormones, chemical signaling, slow response time, covers entire body, slow,

nervous: short term, neurotransmitters, one specific area, fast.

relationship between hypothalamus and pituitary gland

infundibulum connect hypothalamus and pituitary gland

hypophyseal portal system - network of blood vessels that connect hypothalamus to anterior pituitary gland contained in infundibulum.

adenohypophysis vs neurohypophysis

adenohypophysis - anterior pituitary. glandular tissue, manufacters and releases hormones.

neurohypophysis - posterior pituitary + infundibulum. neural tissues and nerve fibers. releases neurohormones from hypothalamus. does not actually make hormones

name, identify, and list secretions of hypothalamus

secretes neurohormones

name, identify, and list secretions of the anterior pituitary gland (adenohypophysis)

secretes:

growth hormone (GH)

follicle stimulating hormine (FSH)

luteinizing hormone (LH)

thyroid stimulating hormone (TSH)

adrenocorticotropic hormone (ACTH)

prolactin

melanocyte stimulating hormone (MSH)

name, identify, and list secretions of the posterior pituitary gland

secretes:

antidiuretic hormone

oxytocin

name, identify, and list secretions of the thyroid gland

thyroxine

calcitonin

name, identify, and list secretions of the parathyroid glands

parathyroid hormine

name, identify, and list secretions of the adrenal cortex and medulla

aldosterone

cortisol

epinephrine

calcitrol (from kidney)

name, identify, and list secretions of the pancreas

insuline

glucagon

ovaries / testes

estrogen

testosterone

progesterone

name, identify, and list secretions of the pineal gland

melatonin

name, identify, and list secretions of the thymus

thymosins (mature T-cells)

name, identify, and list secretions of the heart

atrial naturetic peptide

regions of adrenal cortex

zona glomerulosa, zona fasciculata, zona reticularis