topic 4f -4g

Question 1

Explain the functions performed by neurons and their basic structure

Answer 1

Receive information, process information, conduct the electron signals, transmit information
Dendrites - recive the information from A cell body (soma) - action potential is produced in response to the stimuli
An axon - conduct the action potential into the synapse terminal
Synaptic terminals - where the presynaptic terminal transfers the action potential though the synaptic cleft into the postsynaptic terminal.

Question 2

Describe how neurons can transfer information as an electrical signal, and how this signal may be carried over long distances using action potentials

Answer 2

The inactive neuron has a resting potential (-40 - -90 mV)
When the neuron is stimulated it becomes either more or less negative, the neuron may then reach the threshold value which will then trigger an action potential
The myelin sheath allows the action potential to jump between node to the next quickly.

Question 3

Describe how signals are transmitted across chemical synapses (you should also be able to identify some important neurotransmitters and their roles)

Answer 3

Neurons do not touch, presynaptic neurons are sent through synaptic cleft and received at the adjacent neuron.
- Acetylcholine (skeletal muscle and parasympathetic)
- Dopamine (positive reinforcement)
- Norepinephrine (sympathetic nervous system)
- Serotonin (mood and sleep)
- Glutamate, Glycine, GABA (Excitatory transmitter -fires neurons)
- Endorphins (Influence mood, reduce pain)
- Nitric oxide (memory formation)

Question 4

Describe how nervous systems process information

Answer 4

Intensity of stimulus is directly proportional with the frequency of action potential.
Sensory neuron -> Interneurons -> motor neurons -> effectors

Question 5

Describe the basic organisational structure of nervous systems, and the basic changes that have occurred in the evolution of nervous systems

Question 6

Describe the structures and functions of the human nervous system, be able to distinguish among the central and peripheral nervous systems, the somatic and autonomic nervous systems, and the sympathetic and parasympathetic divisions of the autonomic nervous system

Question 7

Understand the importance of the blood-brain barrier, the structure of the spinal cord, and the functioning of a reflex arc

Question 8

Describe the structure of the vertebrate brain, and how the various portions of the brain have evolved; briefly describe the functions of the medulla, cerebellum, cerebrum, corpus callosum, and limbic system

Question 9

Describe the structure of skeletal muscle

Answer 9

Myosin/actin are filliment think and thin.
Sarcomere are the segments connected by Z discs made of think and thin fliliments .
Myofibril are made from the Sacomere
The sarcoplasmic reticulum surronds the myofibril and high concerntration of calcium ions.

Myosin / Actin -> Sarcomere -> Myofibril -> Sarcoplasmic reticulum -> T Tubules -> Muscle

Question 10

Use the sliding filament model to explain the mechanism of muscle contraction and movement

Answer 10

When the myosin is erected it attaches to the thin filament beside it and becomes bound, which pulls the thin filament towards the centre (flexes).

Question 11

Describe how the body controls contraction of muscles

Answer 11

The body controls muscle contraction via either voluntary or involuntary when the neuron activation which the activation potential ‘excites’ the myosin head which means the electrons cause the head to bond with the thin filament and the muscle pulls tight (flexes)

Question 12

The ways in which cardiac and smooth muscle differ from skeletal muscle

Answer 12

cardiac - one nuclei, involuntary, Striated, connnected via intercalated discs.
smooth - one nuclei, involuntary, not striated, connected via gap junctions
skeletal - many nuclei, voluntary, Striated, connected via Z discs

Question 13

Explain the structure of hydrostatic skeletons

Answer 13

In earthworms, cnidarians and mollusks
There are no joints
Two set of antagonistic muscle , one circular and other longitudinal
The two muscles rotate between contraction to either enlarge or shrink

Question 14

Explain the structure exoskeletons

Answer 14

In arthropods
Restricted to join movement
Antagonistic muscles (flexor and extensors) inside the exoskeleton

Question 15

Explain the structure endoskeletons

Answer 15

Echinoderms and Chordates
Movement occur primarily in joints
Antagonistic muscle attach on opposite sides of the join to contract the join movement.

Question 16

How animals use antagonistic muscle pairs (flexors and extensors) to move body parts

Answer 16

Flexor and extensor work together to move, one is activated at a time either extending or flexing.

Question 17

Describe the structure of the vertebrate skeleton

Answer 17

Cartilage - Soft and flexible made from glycoproteins and collagen with are found in the matrix
There are no blood supply to the cartridge it gains nutrients from diffusion
Provide structure for the respiratory system
The cell in cartilage are called chondrocytes
Ligaments - attach bone to bone
The parallel orientation of collagen in ligaments gives them tremendous strength
Bone
Compact bone - dens and stone made from repeating subunits called osteons which can let arteries and veins flow through. The bone can create hollow tunnels filled with bone marrow, note there is red bone marrow and yellow bone marrow.
Spongy Bone - open network make it porous and light weight

Question 18

How the structure helps the skeleton carry out its various functions

Question 19

Describe the process of bone repair by the body; and list the types of joints found in the vertebrate skeleton and the types of movements each permits

Answer 19

This is done is response to stress
- Consider fracture
A blood clot is formed then the osteoblasts secret a callus made from cartilage
Osteoclasts Break down the cartilage whilst osteoblasts add new bone.
Tendons and ligament can also do this

Joints
Hinge ( linear) and Ball and Socket (Several directional movements)