Endocrine System Flashcards
Why are communication systems important
They help to maintain a constant internal environment and help an organism survive
Define sensitivity
The ability of living organisms to respond or react to a stimulus
How are stimulus detected and transmitted
Stimulus is detected by a receptor, transmitted by a means of nerve impulses or hormones and an effector brings about a response
Define glands
A gland is a group of cells that produces and secretes chemicals for release, such as enzymes or hormones
Define endocrine system
A collection of endocrine glands that secrete hormones directly into the bloodstream to be carried towards target cells or organs. Large number of blood capillaries surrounds endocrine glands
Define hormone
A chemical substance produced by an endocrine gland, carried by the blood, which alters the activity of one or more specific target organs and is then destroyed by the liver
Characteristics of hormones
Small, soluble, Effective in low concentration, Produced by one organ, Secreted into and carried to all parts of the body by blood, Target site different from site where it is synthesised, specific(only organs with specific receptors will respond to hormone)
What gland produces adrenaline
Adrenal glands(above the kidneys)
How does adrenaline stimulate liver and muscles
Speed up breakdown of glycogen into glucose to increase blood glucose levels
How does adrenaline stimulate liver
Increases metabolic rate to release more energy by tissue respiration
How does adrenaline stimulate the heart
Increases rate of heartbeat and cause a rise in blood pressure so oxygen and glucose can be carried faster to muscles
How does adrenaline stimulate the lungs
To increase the rate and depth of ventilation to take in more oxygen
How does adrenaline stimulate the arterioles in the skin
To constrict, causing paleness, channeling more blood to the muscle
How does adrenaline stimulate the pupils
To dilate, enhancing vision
What are two other effects of adrenaline secretion
To stimulate the contraction of hair erector muscle and increase in rate of blood coagulation
When blood glucose is not at norm, what organ secretes hormones
Pancreas
What hormones are secreted when blood glucose increases/decreases norm
Insulin/glucagon
What is purpose of insulin
Blood transports insulin to body cells, liver and muscles to promote uptake of glucose by almost all body cells, especially liver, muscle and adipose tissue. Stimulates liver and muscle to convert excess glucose into glycogen
What is purpose of glucagon
Blood transports glucagon to liver and muscles, glucagon stimulates liver and muscles to convert glycogen to glucose. Increase the release of glucose into blood from liver
What causes type 1 diabetes
Deficiency of insulin, where islets of Langerhans in pancreas cannot produce sufficient insulin
What causes type 2 diabetes
Decreased response to insulin in target tissues. It occurs later in a person’s life and is known s late-onset diabetes.
What are some signs of diabetes mellitus
- Persistently high blood glucose level
- Slow or difficult healing of wounds
- Presence of glucose in urine, especially after meal
Why can glucose be found in urine of diabetic patients
Elevated blood glucose exceeds reabsorption capacity of the kidneys, causing glucose to remain in the filtrate.
Why are diabetic patients normally thirsty
More glucose is concentrated in the urine, water potential in filtrate decreases, less water leaves the filtrate by osmosis, resulting in more water excreted with urine and resulting in excessive volumes of urine
Two similarities in nervous and hormonal coordination
Both provide pathways of communication within the body to coordinate various activities and involve the transmission of messages to the effectors
Difference in nervous and hormonal coordination by nature of message
Nervous: Nerve impulses(electrical) and neurotransmitters(chemical)
Hormonal: Hormones(chemical)
Difference in nervous and hormonal coordination by route of transmission
Nervous: Along neurones
Hormonal: In the bloodstream
Difference in nervous and hormonal coordination by rate of transmission
Nervous: Rapid
Hormonal: Relatively slow
Difference in nervous and hormonal coordination by areas affected
Nervous: Restricted to structures linked to related neurones
Hormonal: Over many parts of the body
Difference in nervous and hormonal coordination by duration of effect
Nervous: Generally short-lived
Hormonal: Generally long lasting
