Multicellular Organisms (Part 1) Flashcards
What does the Central Nervous System (CNS) consist of?
Brain and spinal cord
How is the CNS connected to the rest of the body?
By neurons (nerves)
What is the function of the cerebrum?
Controls conscious thought and memory and personality
What is the function of the cerebellum?
Controls muscle coordination and balance
What is the function of the medulla?
Controls breathing & heart rate
How many chromosomes does the human body have?
46 chromosomes, arranged in 23 pairs.
What is a diploid cell?
Two sets of chromosomes in the same cell.
What is the chromosome complement of human cells?
46
What is a chromosome made out of?
A chromosome is made out of two chromatids, joined at the centromere
What is the pathway of an impulse?
Stimulus → Receptor → Sensory neuron → Inter neuron → Motor neuron → Effector → Response
NOTE: the impulse travels across synapses, releasing chemicals that reach the ((next neuron**.
Give examples of stimuli
Heat, pain, sound, object moving towards you, smell
Give examples of receptors
Skin, eyes, ears, tongue, nose
Give examples of effectors
Muscle, glands
Give examples of responses.
Swallowing, pulling hand away, catching ball
What is a synapse?
The place where two neurons meet
What happens when an impulse reaches a synapse?
When a nerves electrical impulse arrives at the end of one neuron, it causes the release of chemicals. The chemicals diffuse across the synapse and bind with receptors on the next neuron, triggering another impulse
What is the function of the sensory neuron?
The sensory neuron passes information from a receptor to the CNS
Describe the process of mitosis.
- Nucleus contains long uncoiled chromosomes which are difficult to see.
- Chromosomes make copies of themselves and become visible as pairs of identical chromatids.
- Chromosomes line up at the equator of the cell
- Spindle fibres attach to chromosomes and pairs of chromatids are pulled apart.
- Chromosomes move to opposite poles.
- Nuclear membrane forms and cytoplasm divides.
What is the function of the Inter neuron?
The Inter neuron operates within the CNS to transfer impulses from sensory neuron to motor neuron.
What are stem cells?
Stem cells are unspecialised cells involved in growth and repair. They are responsible for the production of specialised cells in animals.
What is the special ability of a stem cell?
Stem cells can self-renew by cell division or have the potential to become different types of specialised cell.
What is the function of the motor neuron?
The motor neuron carries impulses from the CNS to the effector (muscle or gland)
What are hormones?
Chemical messengers
What does a hormone do?
Hormones are carried all over the body to a specific target cell. The hormone binds to a specific receptor and causes changes to occur inside the cell.