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Biology > B5 > Flashcards

B5 Flashcards

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1
Q

What are the human exchange surfaces?

A
  1. Alveloli and capillaries
  2. The digestive system
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2
Q

What diffuses between alveoli and capillaries?

A
  • The job of the lungs is to transfer oxygen into the blood and remove waste carbon dioxide from itself
  • The lungs contain millions od little air sacs called alveoli where gaseous exchange takes place
  • Surrounded by a network of tiny blood vessels called capiillaries
  • Oxygen diffuses from the air in the alveoli into the blood in the capillaries. CO2 diffuses in the opposite direction
  • Specialised to maximise the rate of diffusion of CO2 and O2
    • enormouse surface area
    • A moist lining for dissolving gases
    • Thin walls with Partially permeable membrane
    • A good blood supply
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3
Q

What happens in the digestive system?

A

Dissolved food and water are absorbed
Millions of villi so that digested food quickly absorbs into the blood via active transport or diffusion

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4
Q

What is the (double) circulatory system?

A

The heart, blood vessels and blood
It is a double circulatory system
1) The first one pumps deoxygenated blood from the heart to the alveoli in the lungs to take in oxygen and bring it back to the heart
2) The second one pumps oxygenated blood around to all the other organs

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5
Q

The heart

A

Uses 4 chambers to pump blood around the body(right and left atria and the ventricles
The heart has 4 valves to make sure the blood flowd arounf in the right direction
The valves prevent the backflow of blood

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6
Q

How does blood flow work in the heart?

A

1) The blood flows into the two atria from the vena cava and the pulmonary vein
2) The atria contract pushing the blood into the ventricles
3)The ventricles contract , forcing the blood into the pulmonary artery and the aorta and out of the heart
4) Blood then flows to the organs including the lungs, through the arteries, and returns through the veins
5) The atria fill again and the cycle starts again

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7
Q

What are blood vessels?

A

Transports nutrients to organs and transports waste away.
Three main types
- Arteries
- Capillaries
- Veins

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8
Q

What are arteries?

A

They carry blood pressure:
- Artery walls are strong and elastic
- The walls are thick compared to the lumen(the hole down the middle

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9
Q

What are capillaries?

A
  • Tiny
  • Networks of capillaries are called capillary beds
  • Carries the blood really close to every cell in the body to exchange substances with them
  • Permeable walls, so substances can diffuse in and out
  • Supplies food and oxygen, and takes away wastes such as CO2
  • usually only one cell thick, increasing the rate of diffusion
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10
Q

What are veins?

A

Veins take back blood to the heart:
- The blood here is at a lower pressure, so the walls dont need to be thick
- Larger lumen than arteries to help the flow despite the lower pressure
- Also has valves to prevent the backflow of blood

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11
Q

What is blood?

A

Blood acts as a transport system:
- A tissue; consists of many similar cells working together
- The cells carried are; platelets, white blood cells and red blood cells, and they’re suspended in a liquid called plasma

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12
Q

What is plasma?

A

The liquid part of the blood, it transports:
- Red blood cells, white blood cells and platelets
- Water
- Glucose and amino acids
- Carbon dioxide
- Urea
- Hormones
- Anti-bodies

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13
Q

What are red blood cells?

A

The job of carrying oxygen;
- Small and bioconcave shape to give it a large surface area, increases the rate at which oxygen can diffusse into and out of the cell
- packed with haemoglobin, what gives it the red pigment, contains a lot of iron
- No nucleus
- small and flesible can pass through tiny capillaries

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14
Q

What is The Central nervous system?

A

The system that coordinates a response to a stimulus
Made up of milions of neurones

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15
Q

What is the reflex and how does it work?

A

Reflexes are involuntary actions that stop you from hurting yourself
1) A stimulus is detected
2) The receptor is what detects the stimulus adn sends and electrical impulse that transmitts the sensory neurone
3)The sensory neurone then transmitts the electrical impulse to the relay neurone
4)The relay neurone then transmits the electrical signal to the motor neuron
5)This then allows the effector to cause a muscle contraction to take place to act on the stimulus

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16
Q

How do synapses work?

A

1) An electrical signal arrives at the 1st neurone, which triggers the release of neurotransmitters
2)The neurotransmitters diffuse accross the synaptic cleft
3)The neurotransmitters bind to the receptors on the cell surface of the 2nd neurone to trigger an electrical impulse
4)The neurotransmitters are then reabsorbed by the reuptake channels on the first neurone

17
Q

What is the Brain?

A

The thing in our bodies that is responsible for complex behaviours:
* Cerebral cortex- The outer wrinkly bit, responsible fot consciousness, intelligence, memory and language
* Brain stem - Controls unconscius activities, like breathing and your heartbeat
* Cerebellum - Responsible for conscious movement
* pituitary gland - releases hormones and regulates body temperature
* Hypothalamus- Homeostasis
* Prefrontal cortex - Personality, social behaviour, attention span and memory

18
Q

What are hormones?

A

Chemical messages released from an endorcrine system to go to a target organ

19
Q

What is adrenaline used for?

A
  • Prepares the body for fight or flight
  • Released by adrenal glands2
20
Q

Negative feedback

A

Negative feedback is the action taken by the body to return something to a normal / optimum level following a deviation from that level.

21
Q

Throxine

A

Low level
- Detected by hypothalamus
- Pitiutary gland causes the release of TSH
High level
- Detected by hypothalamus
- Pituitary gland stops release of TSH
This is a process of negative feedback

22
Q

What is the role of ADH?

A

ANTI DIURETIC HORMONE-prevents the loss of water in the body
1)Pituitary gland releases ADH when the body needs to preserve water
2)Gets transported in the blood stream
3)Binfs to receptors on the cell surface of kidneys
4)Water gets absorbed by the kidneyes

23
Q

What is the role of insulin?

A

To maintain the levels of blood glucose concentration
Low concentration
- the pancreas releases glucagon
- the liver and muscles stimulate to break down glucagon into glucose
- raising the blood glucose concentration
High concentration
- pancreas releases insulin into the bloostream
- Acts on live and muscle celld fot glucose uptake, reduces blood glucose concentration and stores as glucagon in cells

24
Q

What is the menstruation cycle?

A

During days 1-7)The uterus lining breaks down
During days 7-14)The uterus lining thickens because of the release fo oestrogen. The uterus becomes more vasvular because it needs a higher blood supply due to it needing to get more nutrients.
Day 14) Ovulation takes place. LH stimulates the release of an egg from a follicle in the ovary to the fallopian tube to prepare itself for fertilisation
Day 15-28) This is where the uterus lining is maintained so the implantation of the egg is sucessful and fertiliastion of the egg is successful. Progesterone and oestrogen help maintain the uterus lining. And fertilisation happens in the fallopian tube
If no egg lands in the uterus wall by day 28 then the lining breaks down and the cycle starts again.

25
Q

What are the roles of the hormones in the menstrual cycle?

A

Four main types:
1. FSH (follicle stumulating hormone)
- released by the pituitary gland
- causes a follicle to mature in one of the ovaries
- stimulates oestrogen production
2. Oestrogen
-released by the ovaries
-causes the lining of the uterus to thicken and grow
3.LH (luteinising hormone)
-released by the pituitary gland
-stimulates ovulation
4. Progestertone
- Released by the ovaries
- Maintains lining of uterus

26
Q

What is homeostasis?

A

The maintenance of a constant internal environment

27
Q

The eye

A

The tissues in the eye are adapted to their features
1. Cornea- transparent outer layer found at front of eye, refracts light into the eye
2. The iris- contains muscles that allow it to control the diameter pupil and therefor how much light enters the eye
3. The lens also refracts light focusing it onto the retina, shape controlled by cilliarty muscles and suspensory ligaments
4. The optic nerve - carries impulses from receptors on the retina to the braim

28
Q

What are ssris?

A
  • Selective Serotosis Reuptake Inhibitors(SSRIs)
    1. Cause of depression: lack of serotonin(not always true)
    2. Function of SSRi:-Block/ inhibit reuptake channels
    -produce more serotonin at presynaptic neuron
    3.Effect of SSRi:-increased concentration of serotonin at in synaptic cleft/broken down
    - taken up by reuptake channels slower
    - more serotonin in synaptic cleft therefore lasts longer
    4.Limitations: - other causes of depression, only shows significant effect in majorly depressed patients
    - takes 6 weeks to work, even though serotonin concentration increases within hours
29
Q

What are neurotransmittters?

A

They are chemical messegeners that your body cannot function without.

30
Q

What are synapses?

A

The small pocket between two neurons where they can pass a message gto communicate

31
Q

What is the endocrine system?

A
  • series of glands found throughout the body
  • All secrete hormones, throughout the body in the blood stream
32
Q

What are hormonal methods of contraception?

A
  • Rely on the release of oestrogen and progesterone-Combined oral contraception pill
  • Oestrogen inhibits productionn of FSH- no egg to be developed or released
  • Progesterone stimulates the production of thick mucus- prevents sperm from reaching egg
  • IUD- placed inside uterus-plastic version stimulates production of thick mucus in the cervix stopping sperm from reaching egg
  • lasts 3 years
33
Q

What are non hormonal methods of contraception?

A
  • Prevent sperm from reaching the egg
  • Condoms-worn over the penis for men, worn in vagina for women- also protects against stds
  • Diaphragm- fits over cervix and blocks sperm from entering the uterus-unreliable
  • Steriliastion-women get there fallopian tubes connected to ovaries so eggs wont reach uterus, mens sperm ducts get cut
  • Not having sex or having it at certain times of the month

Biology (6 decks)

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