Endocrine System Flashcards
How does the endocrine system work?
Endocrine glands produce hormones
Travel in bloodstream to target organs
Hormones bind to specific receptors on the organs
Hormones affect and change in that organ
What is the major function of the endocrine system
Homeostasis
Endocrine vs nervous system in homeostasis
Both needed to regulate homeostasis
Endocrine glands are
The basic unit of endocrine system
How are hormones secreted?
Through the blood
True or false: the endocrine glands have ducts
False they do not have ducts
What types of hormones are there?
Proteins (peptide hormones)/amino acids
Steroids (lipids)
Steroids are?
Water insoluble
Receptors in cytoplasm
Proteins are?
Water soluble
Receptors on cell membrane
What is half life
The time it takes for the body to eliminate or metabolize 1/2 the circulating hormone
Protein hormones 1/2 life
Shorter
Lipid/steroid 1/2 life
Longer
Regulation of hormones run on what kind of feedback?
Negative feedback system
Major endocrine glands
Pituitary
Thyroid
Parathyroid
Adrenal
Pancreas
Gonads(ovaries/testes)
What controls anterior pituitary
Hypothalamus
The hypothalamus sends what to where?
Releasing hormones
Inhibitory hormones
To anterior pituitary
Pituitary gland aka
Hypophysis
Anterior pituitary gland
Adenohypophysis
Glandular tissue
Posterior pituitary gland
Neurohypophysis
Nervous tissue
Which of the endocrine glands is considered the “master” gland?
Pituitary
How is the anterior PG connected to the hypothalamus?
Portal system of blood vessels
What 7 hormones are made/secreted by APG?
Growth
Prolactin
Thyroid stimulating
Adrenocortropic
Follicle stimulating
Luteinizing
Melanocyte stimulating
Growth hormones does?
Growth of young animals
Regulation of metabolism
Muscles,bone and other tissues
Growth hormone disorders
GH defiance-dwarfism
GH excess in adult cat- acromegaly
Prolactin
Stimulates growth of mammary glands and milk production
Thyroid stimulating hormone(TSH)
Thyroid gland
Adrenocorticotropic hormone (ACTH)
Adrenal cortex
Also released w/sympathetic nervous system stim
Follicle stimulating hormone-FSH female
Stimulates follicles in ovary growth
Luteinizing hormone-LH female
Causes ovulation-the follicle ruptures
Follicle stimulating hormone-FSH male
Stimulates sperm development
Luteinizing hormone-LH male
Stimulates testosterone production
Melanocyte stimulating hormone-MSH
Melanocytes in skin
Posterior Pituitary Gland
Antidiuretic Hormone (ADH)
Oxytocin
Antidiuretic Hormone
Acts on kidney tubules; water loss
Released w/dehydration
Oxytocin
Released into Mammary glands and uterus
Thyroid gland
On either side of trachea caudal to larynx
Two lobes connected by “isthmus”
Thyroid gland anatomy
Thyroid follicles
Parafollicular cells
Thyroid follicles
Colloid in middle
Thyroid hormone precursor
Parafollicular cells
On the outer rim of follicular cells; smaller
Thyroid hormones
T3- triiodothyronine **active hormone
T4-tetraiodothyronine
Thyroid hormone job
Target all cells
Increase cellular metabolism
Maintains body heat
Hypothyroidism
Most common in dogs
Obesity
Lethargy
Alopecia
Intolerance to cold
Hyperthyroidism
Common in cats
Enlarged gland
Weight loss w/increased appetite
Scruffy
Vomiting
Diarrhea
PU/PD/PP
Rapid heart rate
Vocal
Calcitonin
Produced by Parafollicular cells
Calcium regulation
Parathyroid gland
Found on, in or near the thyroid gland
Parathyroid hormone (PTH)
Calcium regulation
Decrease blood calcium leads to increased PTH release
Adrenal glands gross anatomy
Just under the kidneys
Parts of the adrenal glands
Capsule
Cortex
Medulla
Adrenal cortex
Zona Glomerulosa
Zona fasciculata
Zona reticular is
Zona glomerulosa
Mineralocorticoids
Target=kidney
Na+ and K+ balance
Water balance
Zona Fasciculata
Glucorticoids
Targets=all cells
Cortisol and cortisone
Immune system suppression
Zona Reticularis
Androgens
Estrogen and testosterone
Effects are minimal
Hyperadrenocorticism
Cushing’s Disease
Hypoadrenocorticism
Addison’s Disease
Adrenal medulla
Derived from nervous tissue
Epinephrine
Norepinephrine
Pancreas
Located adjacent to the duodenum
Extends across cranial abdomen
Pancreas functions
Exocrine:digestive enzymes
Endocrine: pancreatic islets
Pancreatic Islets (Islets of Langerhans)
Alpha cells
Beta cells
Delta cells
Alpha cells
Glucagon->liver->increased blood glucose
Gluconeogenesis & Glycogen breakdown
Beta cells
Insulin: allows cells to take in glucose, stimulates glucose to be stored as glycogen in the liver
Blood glucose drops
Glucagon released
Blood glucose increased
Insulin released
Diabetes Mellitus
Lack of insulin
Persistent HYPERglycemia
Signs of diabetes mellitus
PU/PD
Polyphasic
Diabetic Ketoacidosis DKA
Long standing, untreated diabetes mellitus becomes an emergency
Interstitial (Leydig) cells
Testosterone
Testosterone targets
Bone
Muscle
Prostate gland
Penis
Brain
Testosterone is responsible for
Libido and 2 degree sex characteristics
Estrogen targets
Mammary glands
Bone
Fat
Uterus
Produced by follicles in ovary
Estrogen
Estrogen is responsible for
Libido
Estrus(heat)
2 degree sex characteristics
Produced by the corpus Luteum
Progesterone
Progesterone targets
Uterus
Progesterone is responsible for
Maintaining pregnancy
Kidney
Erythropoietin
Targets bone marrow
Stimulates red blood cell production
Placenta
Estrogens
Progesterone
Equine chorionic gonadotropin
Thymus
Thymosin
Immune system regulation
Pineal body
Melatonin
Wake/sleep cycles
Possibly timing of estrus cycles
GI secretions
Stomach- gastrin
Sm intestine- secretin, cholecystokinen (CCK)
Hormone- like substances
Prostaglandins
