Lecture Flashcards
Second messenger system of the body
Uses chemical messages (hormones)
that are released into the blood
Endocrine
Hormones control several major processes
Reproduction
Growth and development
Mobilization of body defenses
Maintenance of much of homeostasis
Regulation of metabolism
Hormones are produced by
specialized cells
Cells secrete hormones into
extracellular fluids
Amino acid-based hormones
Proteins Peptides Amines
made from cholesterol
steroids
made from highly
active lipids
Prostaglandins
Effects Caused by Hormones
Changes in plasma membrane permeability or electrical state
Synthesis of proteins, such as enzymes
Activation or inactivation of enzymes
Stimulation of mitosis
Diffuse through the plasma membrane of target cells
Enter the nucleus
Bind to a specific protein within the
nucleus
Bind to specific sites on the cell’s DNA
Activate genes that result in synthesis of new proteins
steroid action hormone
Hormone binds to a membrane receptor
Hormone does not enter the cell
Sets off a series of reactions that activates an enzyme
Catalyzes a reaction that produces a second messenger molecule
Oversees additional intracellular changes to promote a specific response
nonsteroid hormone action
Hormone levels in the blood are maintained
negative feedback
Size of a grape
Hangs by a stalk from the hypothalamus
Protected by the sphenoid bone
Has two functional lobes
pituitary gland
Anterior pituitary –
Posterior pituitary
- Gandular tissue
- Nervous tissue
General metabolic hormone
Major effects are directed to growth of
skeletal muscles and long bones
Causes amino acids to be built into proteins
Causes fats to be broken down for a source of energy
Growth Hormone
Stimulates and maintains milk production
following childbirth
Prolactin
Regulates endocrine activity of the adrenal
cortex
Adrenocorticotropic hormone
Influences growth and activity of the thyroid
Thyroid-stimulating hormone
Regulate hormonal activity of the gonads
Gonadotropic hormones
Stimulates follicle development in ovaries
Stimulates sperm development in testes
Follicle-stimulating hormone
Triggers ovulation
Causes ruptured follicle to become the corpus luteum
Stimulates testosterone production in males
Luteinizing hormone
Release of hormones is controlled by releasing and inhibiting hormones produced by
hypothalamus
Stimulates contractions of the uterus during
labor
Causes milk ejection
Oxytocin
Can inhibit urine production
In large amounts, causes vasoconstriction leading to increased blood pressure
Antidiuretic hormone
Found at the base of the throat
Consists of two lobes joined by central
mass or isthmus
Thyroid Gland
Thyroid glands produce two hormones:
Thyroid and Calcitonin
Composed of two active iodine-
containing hormones
thyroxine and triiodothyronine
secreted by thyroid follicles
Thyroxin
conversion of T4 at target tissues
Triiodothyronine
Decreases blood calcium levels by causing its deposition on bone
Antagonistic to parathyroid hormone
Calcitonin
Tiny masses on the posterior of the thyroid
Secrete parathyroid hormone
Stimulate osteoclasts to remove calcium
from bone and release it into the blood
Stimulate the kidneys and intestine
Parathyroid Glands
Two glands of adrenal glands
Cortex and Medulla
outer glandular region in three
layers
Cortex
inner neural tissue region
Medulla
Produced in outer adrenal cortex
Regulate mineral content in blood, water, and electrolyte balance
Target organ is the kidney
Production stimulated by renin and
aldosterone
Production inhibited by atrial natriuretic peptide
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Mineralocorticoids
Produced in the middle layer of the adrenal cortex
Promote normal cell metabolism
Help resist long-term stressors
Released in response to increased blood levels of ACTH
Glucocorticoids
Produced in the inner layer of the adrenal
cortex
Androgens (male) and some estrogen (female)
Sex hormones
Produces two similar hormones in adrenal medulla. Deals with short term stress
Epinephrine and Norepinephrine
allows glucose to cross plasma membranes into cells from beta cells
insulin
allows glucose to enter the blood from alpha cells
glucagon
Found on the third ventricle of the brain Secretes melatonin
Helps establish the body’s wake and sleep cycles
Pineal Gland
Located posterior to the sternum in upper thorax
Largest in infants and children
- Produces
Thymus
2. Thymosin
Produced by Graafian follicles of the ovaries
or the placenta
Stimulates the development of secondary female characteristics
Matures female reproductive organs
Helps prepare the uterus to receive a fertilized
egg
Helps maintain pregnancy
Estrogens
Produced by the corpus luteum
Acts with estrogen to bring about the menstrual cycle
Helps in the implantation of an embryo in the uterus
Progesterone
specialized lymphatic capillaries
Lacteals
collections of lymphatic tissue)
Peyer’s patches
saclike first part of the large intestine
Cecum
Accumulation of lymphatic tissue that sometimes becomes inflamed
appendix
Ascending
Transverse
Descending
S-shaped sigmoidal
colon
A clot in an unbroken blood vessel
Can be deadly in areas like the heart
Thrombus
A thrombus that breaks away and floats freely in the bloodstream
Can later clog vessels in critical areas such as the brain
Embolus
Platelet deficiency
Even normal movements can cause bleeding from small blood vessels that require platelets for clotting
Thrombocytopenia
Hereditary bleeding disorder
Normal clotting factors are missing
Hemophilia
Injured tissues release thromboplastin
PF3 (a phospholipid) interacts with thromboplastin, blood protein clotting factors, and calcium ions to trigger a clotting cascade
Prothrombin activator converts prothrombin to thrombin (an enzyme)
Coagulation
Anchored platelets release serotonin
Serotonin causes blood vessel muscles
to spasm
Spasms narrow the blood vessel, decreasing blood loss
Vascular Spasm
Collagen fibers are exposed by a break in a blood vessel
Platelets become “sticky” and cling to fibers
Anchored platelets release chemicals to attract more platelets
Platelets pile up to form a platelet plug
Platelet Plug Formation
regulates osmotic pressure
Albumin
help to stem blood
loss when a blood vessel is injured
Clotting proteins
help protect the body from antigens
Antibodies
red blood cells
Erythrocytes
white blood cells
Leukocytes
cell fragments
Platelets
The main function is to carry oxygen
Erythrocytes
Iron-containing protein
Binds strongly, but reversibly, to oxygen
Hemoglobin
Crucial in the body’s defense against disease
These are complete cells, with a nucleus and organelles
Able to move into and out of blood vessels (diapedesis)
Leukocytes
Granules in their cytoplasm can be stained
Include neutrophils, eosinophils, and basophils
Granulocytes
Lack visible cytoplasmic granules
Include lymphocytes and monocytes
Agranulocytes
Multilobed nucleus with fine granules
Act as phagocytes at active sites of infection
Neutrophils
Large brick-red cytoplasmic granules
Found in repsonse to allergies and parasitic
worms
Eosinophils
Have histamine-containing granules
Initiate inflammation
Basophils
Nucleus fills most of the cell
Play an important role in the immune response
Lymphocytes
Largest of the white blood cells
Function as macrophages
Important in fighting chronic infection
Monocytes
Derived from ruptured multinucleate cells (megakaryocytes)
Needed for the clotting process
Platelets