B5 Flashcards
(36 cards)
What does the lungs do?
Transfers Oxygen to the blood
-Contain alveoli where oxygen diffuses into and carbon dioxide diffuses out.
How are the alveolar specialized to maximise the rate of diffusion?
- Large surface area
- Very thin walls
What is the role of the Villi?
The Villi increases the surface area so that digested food can be absorbed quickly into the blood.
What is the role of the Arteries?
To carry blood away from the heart
- thick walls as blood come out at a high pressure
- walls able to spring back(extend)
What is the role of the Capillaries?
To exchange substances in blood
- supply oxygen and take away carbon dioxide
- 1 cell thick to allow fast diffusion
What is the role of the Veins?
To carry blood back to the heart
- large lumen, thin walls as blood travels at a slow pace
- contain valves to prevent back flow
What is the role of Plasma?
To transport substances round your body
-E.g, red blood cells and white blood cells
What is the role of the red blood cell?
To carry oxygen around the body.
What does the Central Nervous System do?
The CNS coordinates a response and sends a message to an effector which performs the response.
What do Neurons do?
Electrical impulses are passed along the axon of a neuron, which is surrounded by a fatty sheath. The fatty sheath insulates and speeds up the impulse.Neurons have branched endings, where they connect with other neurons.
What does the brain consist of?
Brain stem
-controls unconscious activities, e.g breathing.
Cerebral Cortex
-Responsible for memory and language etc.
Cerebellum
-Responsible for conscious movement
What methods do we use to study the brain?
- Study patients with brain damage
- Electrically stimulate the brain
- fMRI scans
Why is treating brain problems tricky?
- Treatment could lead to permanent damage
- Ethical issues-e.g some people may not be able to consent
- Some areas of the brain extremely hard to access
What are Hormones?
Hormones are chemical messengers sent in the blood
What is Adrenaline?
Adrenaline is a hormone released by the adrenal glands.
Adrenaline increases blood flow-faster heart rate, more aerobic respiration
What is Negative Feedback?
Negative feedback is when the body triggers a response when something is too high or too low to put it back to normal level.
What are the 4 stages of the menstrual cycle?
Stage 1: Lining of the uterus breaks down
Stage 2:Uterus is repaired in preparation for an egg.
Stage 3:An egg develops
Stage 4:If no fertilized egg has landed on the uterus by
day 28, the process starts again.
What 4 hormones control the menstrual cycle?
FSH -cases egg to mature OESTROGEN -cause uterus lining to thicken LH -allows egg to be released PROGESTERONE -maintains the lining of the uterus in preparation fertilized egg.
How can hormones be used to treat infertility?
Some women’s levels of FSH are too low so the egg cannot develop
-So FSH can be injected into a woman.
What do Hormonal Contraceptive methods do?
- Helps block the entrance to the uterus to prevent sperm from reaching an egg
- Thins lining of the uterus to reduce the chance of a fertilized egg implanting.
What are the disadvantages of contraceptives?
- side affects
- barrier methods may not work
- length of hormonal contraceptive
- STIs
What is Homeostasis?
Maintaining a constant internal environment
-conditions are kept within a narrow range
What negative feedback occurs when your body temperature is too hot?
- Hairs lie flat
- Sweat
- Vasodilation
What negative feedback occurs when your body temperature is too cold?
- hairs stand up to insulate you
- little sweat produced
- vasoconstriction
