Endocrine System

chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body

target cells

more than 70

• hormones that coordinate slower but longer- acting responses including
• reproduction 
• development
• energy
• metabolism
• growth
• behavior

high-speed electrical signals along specialized cells called neurons which regulate other cells

• chemicals that have been identified to interfere with hormone signaling
• insecticides, herbicides, dyes, plastics, detergents
• DDT, PCB's and red dye #3

• chemical signals bind to receptor proteins on target cells (only target cells respond to the signal)
• these include 
• hormones
• local regulators
• neurotransmitters
• neurohormones
• pheromones

• substances onto body surfaces or into body cavities
• tear ducts
• sweat glands
• salivary glands
• liver
• pancreas
• mammary glands
• stomach

• chemical signals that travel over short distances by diffusion
• help regulate blood pressure, nervous system function, and reproduction
• divided into two types: paracrine and autocrine

signals act on cells near the secreting cell

signals act on the secreting cell itself

synapses

neurons often secrete chemical signals called neurotransmitters

• diffuse a short distance to bind to receptors on the target cell
• play a role in
• sensation
• memory
• cognition 
• movement

• chemical signals that are released from the body and used to communicate with other individuals in the species
• mark trails to food sources, warn of predators, and attract potential mates
• (7 types of pheromones)

cause conspecifics to flee

initiate behavior

cause short term changes

cause developmental changes

attract mates

• polypeptides (proteins and peptides)
• Amines derived from amino acids
• steroid hormones

• aggression
• violence
• mania
• psychosis
• liver damage
• gynecomastia (male develop breasts)
• testicular atrophy

• lipid soluble
• water soluble do not

the location of receptors inside or on the surface of target cells

exocytosis, travel freely in the bloodstream, and bind to cell-surface receptors

cell membranes, travel in bloodstream bound to transport proteins, and diffuse through the membrane of target cells

binding of a hormone to its receptor intitates a signal transduction pathway leading to responses in the cytoplasm, enzyme activation, or a change in gene expression

gene expression

• the cytoplasm or nucleus
• protein-receptor complexes then act as transcription factors in the nucleus, regulating transcription of specific genes

• in the skin of vertebrates
• feathers and fur block the skin
• oily secretions on fur generate the vitamin and licking absorbs it

• to the liver
• converted to physiological active form

• calcium and phosphate in the blood
• cell proliferation and aptosis
• neuromuscular function

• either an overbalance or a limitation of a hormone
• gland hyposecretion
• gland hypersecretion
• tumor
• usually multiple symptoms

• adrenal glands do not produce sufficient glucorticoids 
• symptoms
• fatigue
• light headedness
• muscle weakness
• fever
• vomiting
• hyperpigmentation

• regulate immune responses
• cardiac function
• metabolism
• and homeostatic responses

• hypothalamus to produce CRH
• CRH recieved by the pituitary which then produces ACTH to signal the adrenal glands to produce more glucocorticoids

• MSH and ACTH share the same precursor molecule POMC
• with the upregulation of ACTH there is also an increase in MSH
• darkening of creases of the hands, inside of the cheeks and old scars are common

• oral steroids
• genetic
• autoimmune
• medicines for other illnesses interfere with steroid synthesis
• infections damaging the adrenal glands