C3.1 (Integration of Body system)

Question 1

Define system integration:

Answer 1

Cell -> Tissues -> Organs -> Body systems -> Organisms

Question 2

Define the system integrations

Answer 2

1. Cells: Smooth muscle cell // guard cell
2. tissue: muscular wall // stoma
3. organ: bladder // leaf
4. organ system: nervous, respiratory, circulatory, digestive, excretory, muscular, skeletal, integumentary, reproductive, endocrine // vascular
5. organism: white-tailed deer // magnolia tree

Question 3

What is an emergent property?

Answer 3

The whole is greater than the sum of the parts; arise due to integration of subsystems

Question 4

Emergent property in cheetah:

Answer 4

• Large heart + lungs
• Flexible spine, acts as spring while running
• Lead body, long legs
• long muscular tail, acts as stabilizer when running at high speed

Question 5

State the two primary mechanisms by which animals integrate organ systems.

Answer 5

Hormonal and nervous signaling

Question 6

What is Autonomic neurvous system?

Answer 6

• Communication w/out conscious knowledge
• ex regulation of heart rate, blood glucose evels…

Question 7

Hormone vs nervous signals

Answer 7

Similarities
– both used for communication between cells/tissues/organs
– both can work over long distances

– both under control of the brain

– both use negative feedback

Differences

Hormonal -> Chemical
* Nervous* -> Electrical nerve impulse

hormonal -> Slower
Nervous -> Faster

Hormonal -> Transmits through bloodstream
Nervous -> Transmits by neurons

Hormonal -> Only control involuntary
Nervous -> Can control both

Question 8

Function of brain

Answer 8

• Regulate + monitor unconscious body processes
• processes information
• speech, emotions, problem solving
• learning and memory

Question 9

Different kinds of receptors that send info to brain

Answer 9

1. Photoreceptors -> Visual info
2. Chemoreceptors -> tasting
3. Thermoreceptors -> temp changes
4. Mechanoreceptors -> Sound vibrations

Question 10

Different kinds of receptors that send info to brain (Subconscious level)

Answer 10

1. Osmoreceptors -> sense solute + water content of blood
2. Barroreceptors -> Sense blood pressure
3. Proprioceptors -> Provide balance + coordination

Question 11

4 main areas of brain

Answer 11

1. Cerebrum: Responsible for conscious activities
2. Cerebellum: Coordinates voluntary movements, controls balance, and equilibrium allows precise coordination of movement
3. Brainstem: Responsible for subconsious functions/ associated with ANS
4. Medulla oblongata: located in Brain stem regulates breathing + heart rate

Question 12

What organs are in the central nervous system?

Answer 12

Spinal cord and brain

Question 13

two main tissue types of the central nervous system.

Answer 13

– white matter (composed of axons of neurons, carries neural impulses to and from brain)

– grey matter (contains neurons and synapses)

Question 14

Outline the function of sensory neurons

Answer 14

• Carry action potential from receptors to CNS

Question 15

Outline the function of motor neurons.

Answer 15

– motor cortex: in cerebrum: sends action potential, located in the most posterior portion of frontal lobe of cerebrum

– motor neurons: carry action potential from CNS to muscles (effectors), form synapses called motor end plate / neuromuscular junctions with muscle fibres

Question 16

Define neuron and nerve

Answer 16

neuron: cell of nervous system

nerve: group of myelinated or unmyelinated neurons

Question 18

Pain reflec arc

Answer 18

1. receptor cells detects the painful stimulus
2. Sensory neurons Transmit electrical impuls to CNS
3. The Interneurons located in the grey matter of the brain and spinal cord, connects sensory and motor neurons
4. Synapses transmit the signal between neurons
5. Motor neurons carry the impulse from the CNS to an effector
6. Effector carries out the response of stimulus
7. Response is a Reflex action including an involuntary, rapid response to a stimulus

Question 19

Function of Cerebellum

Answer 19

1. motor cortex initiates muscle contraction
2. cerebellum receives feedback impulses
3. cerebellum send out impulses to coordinate movement
4. smooth and balanced muscular activity, coordinated movements

Question 20

What is the circadian rhythm?

Answer 20

pattern or physiology based on a 24-hour cycle e.g. wake and sleep cycle

Controlled by Secretion of metaltonin by pineal gland

Question 21

Effects of epinephrin on body

Answer 21

• contraction of skeletal muscles

– accelerated heart rate

– vessel dilation: increased blood supply to muscles

– increased blood sugar levels by stimulating glycogen conversion to glucose in liver

– pupil dilation

– increased ventilation rate + dilation of air passages – more air received by lungs to supply O2 and CO2

Question 22

Outline the role of the hypothalamus as a link between the nervous and endocrine system

Answer 22

• Small little region in brain
• Specialised areas: nuclei, each nucleus has 1+ specific control systems (sensors for blood temp, blood glucose levels…)
• Receive signals from sense organs by
• Has a anterior and posterior lobes, each secrete hormones into blood capillaries

Question 23

Anterior vs Posterior lobe

Answer 23

Anterior -> Makes + stores own hormones

Posterior -> Stores hormones mad by hypothalamus

Question 24

What are body processes that are monitored by the hypothalamus?

Answer 24

• Osmoregulation (Concentration of blood)
• Puberty (Secretes GnRH, that stimulates LH and FSH)

Question 25

Described the structures and functions of nervous tissue that can **regulate heart rate**, including the role of the medulla oblongata, sympathetic nerve, vagus nerve, baroreceptors and chemoreceptors. (5)

Answer 25

1. **Cardiovascular centre** receives sensory input from **Baroreceptors** and **chemoreceptors** which are located in the **aorta** or **carotid arteries** 2. Signal to the **medulla oblongata 3. Nerves will reach the pacemakers 4. **pacemaker** sets heart rate by initiating each beat 5. **Pacemaker** also increases heart rate in response to *epinephrine* in blood

Question 26

What are baroreceptors?

Answer 26

In walls of **aorta** and **carotid arteries** allowing to control *blood pressure* by **negative feedback**

Question 27

What are chemoreceptors?

Answer 27

Located in **aorta** and **carotid arteries** allows the control of **Blood O2 concentration and pH level** by *negative feedback*

Question 28

Feedback loop that regulates **ventilation rate**

Answer 28

1. **Chemoreceptors** in **respiratory** center of medulla oblongata detects a fall in blood pH, resulting in a **rise in CO2** in blood 2. Respiratory center sends more **nerve impulses** to external intercostal muscles, causing them to **contract** more frequently and forcefully, **expanding the lungs** 3. Increase rate and depth of breathing, **CO2** can be **removed** from the body faster

Question 29

Outline the role of the central and enteric nervous systems in movement of material into, through and out of the gut.

Answer 29

**Swallowing**: - Muscle in tongue controlled by **brain** - Signals from receptors pass to brain stem, stimulates food to be pushed down (**involuntary**) **Peristalsis** - wave of contraction + relaxation in wall of gut - Moves in a **circular** and **logitudinal** movement

Question 30

Positive/ negative tropism

Answer 30

**tropism**: differential growth to directional stimuli **positive tropism**: growth towards the stimulus **negative tropism**: growth away from stimulus

Question 31

Outline gravitropism in roots and stems.

Answer 31

**negatively gravitropic** (grow upwards) **positively gravitropic** (grow downward to absorb water and minerals + anchor the plant, same direction as gravity)

Question 32

Define **phytohormone**

Answer 32

plant hormones which are signalling chemicals that control growth, development and response to stimuli in plants

Question 33

2 roles of auxin

Answer 33

1. Maintain concentration gradient of **phytohormones** 2. Promotes stem growth and causes different growth responses of phototropism

Question 34

Describe the mechanism of movement of auxin into and between plant cells. ​(5)

Answer 34

1. Auxins enter cells by **passive diffusion** 2. **trapped inside** (Because cytoplasm is slightly alkaline** 3. Plant cells produce **auxin efflux carriers** to pump auxins with negative charge across **plasma membrane** into **cellulose cell wall** 4. Auxins reverts to an unchatged state, diffusing to lighter to darker side 5. Plant cell coordinates **production** of auxin efflux carriers on **the same side** until high concentration

Question 35

Outline the source and transport of auxin and cytokinin in plants.

Answer 35

**auxin**: cell elongation; produced in **shoot tips**, transported in phloem down stems and into roots; inhibits growth of axillary buds **cytokinin**: cell differentiation; produced in root tips, transported in xylem uproots and into stems

Question 36

List changes that occur to a fruit as it ripens. (4)

Answer 36

1. **color** of fruit changes from 2. cell wall are partly digested, **softening the flesh** 3. **acids and starch are converted to sugar**, making the fruit palatable 4. volatile substances are synthesized to give the **fruit a distinctive scent**

Question 37

Describe the positive feedback mechanism of fruit ripening.

Answer 37

1. **ethylene** stimulates ripening 2. ripening fruits **release ethylene** as a volatile vapour which *diffuses* to other fruits and initiates their ripening 3. **rapid** and **synchronized** ripening of fruits

Question 38

What is Phototropism

Answer 38

The growth of plants towards a source of light – This is a **positive** tropic response, because the plants grow **towards** the stimulus

Question 39

How do plants respond to environmental cues?

Answer 39

By producing hormones called **phytohormones** e.g. **Auxin** (results in cell elongation), **cytokine** (increases rate of cell division), **ethylene** (promotes fruit ripening)

Question 40

How is auxin concentrated?

Answer 40

– Concentration gradient of the auxin is set up by **auxin efflux carriers**, allowing auxin to diffuse into plant cells – If needed, plants can distribute efflux carriers predominantly on one side of a series of adjoining cells, encouraging one-way movement of auxin through that series of cells – This is a form of **active transport due to ATP requirements

Question 41

What happens during fruit ripening?

Answer 41

- Fruits produce a gas called **ethylene** – This gas affects **nearby** fruits – When one fruit begins to ripen, the gas released will spread to adjacent fruits, causing them to start to **ripen at the same time** – This is a **positive feedback** mechanism as more ethylene causes more fruits to ripen, which in turn causes more ethylene gas to be produced

Question 42

What is the advantage of ethylene production?

Answer 42

Animals are attracted to the ripe fruit, eat the fruit and deposit the seeds away from the plant

Question 43

Outline how the hormone auxin controls phototropism in plant shoots (6)

Answer 43

– Phototropism is the growth towards light – Auxin is moved to the shadier side of the plant stem – Moved by auxin efflux pump – Auxin promotes cell wall acidification – Causes more growth on the shadier side – Protons activate expansions, which breaks the hydrogen bonds between microfibers. Water enters, causing cell to expand

Question 44

What organs are involved in Nervous system, what about endocrine system?

Answer 44

**Nervous system** -> Brain, spinal cord, nerves **Endocrine system** -> Glands

Question 45

What are ventilation rates?

Answer 45

Number of breaths per unit in time

Question 46

What is **peristalsis**?

Answer 46

involuntary muscle movement that occurs in your digestive system