ANAT LEC Ch. 19 - The Endocrine Sys

Endocrine cells

Glandular secretory cells that release hormones DIRECTLY into Interstitial FLUIDS, LYMPH, or BLOOD

Amino Acid Derivatives

Small molecules, structurally similar to AAs

• Ex. Thyroid Hormone

Peptide Hormones

Composed of chains of AAs

• Largest group of chains of AAs

• Ex. Growth Hormones

Lipid Derivitives

Divided into 2 groups

1. Eicosanoids

2. Steroids: Structurally similar to Cholesterol

   • Ex. Sex Hormones

Target Cell

• Specific cells w/Receptors that bind the hormones

• One for ea Horomone

Endocrine activity is triggered by

• Hormonal Stimulation

• Humoral Stim

• Neural Stim

Neural Stim

Arrival of Neurotransmitters at the neuroglandular junction

Humoral Stim

Changes to extracellular fluid

Hormonal Stimulation

Arrival or Removal of specific hormones

Pituitary Gland

(Adenohypophysis)

Contains 3 Regions

1. Pars Distalis

2. Pars Tuberalis

3. Pars Intermedia

Follicle-Stimulating Hormone (FSH)

• Follicle development & Estrogen secretion in Fem

• Sperm maturation in Male

Luteinizing Hormone (LH)

• Causes Ovulation, Corpus Luteum formation, & progesterone secretion in Females

• Targets interstitial cells in testes for Males

Prolactin (PRL)

Targets female mammary glands & causes production of milk

Thyroid Follicles

Manufacture, store, & secrete thyroid hormones

• Lined w/Follicular cells

  • T-Thyrocytes → Transport IODINE

• Parafollicular Cells (C Thyrocytes) → produce Calcitonin

  • Regulates CALCIUM intake

Thymus

Produces hormones important in maintaing IMMUNE Defense

• Reaches max size prior to Puberty

• Decreases size thru adulthood

Adrenal Glands

Divided in to 2 regions:

Cortex & Medulla

Pancreas

Both Exocrine & Endocrine

Secretes: Glucagen (Alpha cells), Insulin (Beta Cells), Somatostatin (Delta Cells), Pancreatic Polypeptide (F cells)

UNDERproduction of GH (Growth Hormone) results in

Pituitary Growth Failure

• Retarded growth, abnormal fat distribution, low blood glucose hrs after a meal

UNDERproduction of Insulin results in

Diabetes Mellitus

• High blood glucose, imparied glucose utilization, dependence on lipids for energy, glucosuria, ketosis

OVERproduction of GH (Growth Hormone) results in

Giantism (children)/ Acromegaly (adults)

• Excessive growth in stature of a child or in face & hands in an adult

OVERproduction of INSULIN results in

Low blood glucose levels, possibly causing coma