Acknowledgement of Academic Responsibility
Answers to assignment questions must be original; that is, you must write them all yourself. You can base your answers
on information in the course textbook or other sources, but if you use sources other than the textbook, you must cite
them appropriately.
Plagiarism is a form of academic misconduct that has serious consequences. It is your responsibility to read and
understand the statement on Academic Integrity in the Student Manual and the Student Academic Misconduct Policy in
the AU undergraduate Calendar. If plagiarism is detected, and if an investigation concludes that you must rewrite the
assignment, then your assignment grade will be reduced by 20 marks.
“By filling in my name and ID number below, I acknowledge my responsibility to academic integrity and confirm that
none of the wording in my answers has been copied or plagiarized in any way from any source.”
Student’s name: BLESSING ADU
Student's AU ID number: 3450031
NOTE: The assignment will not be marked if it is submitted without the above two lines filled in.
BIOL 235
Assignment 2 :: Biology 235: Human Anatomy and Physiology 1
,Assignment 2
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
Total mark = 93.5%
1. Name the type of joint, and list the movements permitted at the shoulder joint. Under each
movement’s name, list the names of the muscles responsible for each of these movements
along with descriptions of their bone insertion.
A joint is also known as articulation or arthrosis. It is a point of contact between two bones,
between bone and cartilage, or between bone and teeth. The types of joint includes fibrous
(immovable), Cartilaginous (partially moveable) and the Synovial (freely moveable) joint.
The shoulder joint also known as the humeroscapular joint, is a synovial ball-and-socket
joint formed by the head of the humerus and the glenoid cavity of the scapula. This joint
allows abduction, adduction, flexion, extension, hyperextension, medial rotation, lateral
rotation and, circumduction of the arm. The muscles responsible for each movement are
discussed below;
Abduction√ of the arm- the muscle includes the lateral fibers of the deltoid, with its
insertion at the deltoid tuberosity of the humerus, and the supraspinatus, with its
insertion at the greater tubercle of the humerus.√
Adduction √of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the teres
major with its insertion at the medial lip of the intertubercular sulcus of the humerus,
the latissimus dorsi, with its insertion at the intertubercular sulcus of the humerus,
and the coracobrachialis, with its insertion at the middle of the medial surface of the
shaft of the humerus.
Flexion of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the deltoid,
with its insertion at the deltoid tuberosity of the humerus, the coracobrachialis, with
its insertion at the middle of the medial surface of the shaft of the humerus, and the
biceps brachii, with its insertion at the radial tuberosity of radius and bicipital
aponeurosis.√
Extension of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the
latissimus dorsi, with its insertion at the intertubercular sulcus of the humerus, the
deltoid, with its insertion at the deltoid tuberosity of the humerus, the
coracobrachialis, the teres major, with its insertion at the medial lip of the
Assignment 2 :: Biology 235: Human Anatomy and Physiology 2
, intertubercular sulcus of the humerus, and the teres minor, with its insertion at the
greater tubercle of the humerus.√
Medial rotation of the arm – the muscles includes the pectorial major, with its
insertion at the greater tubercle and lateral lip of intertubercular sulcus of the
humerus, the latissimus dorsi, with its insertion at the intertubercular sulcus of the
humerus, the deltoid, with its insertion at the deltoid tuberosity of the humerus, the
subscapularis, with its insertion at the lesser tubercle of humerus, and the teres
major, with its insertion at the medial lip of the intertubercular sulcus of the
humerus.√
Lateral rotation of the arm- the muscles include the deltoid, with its insertion at the
deltoid tuberosity of the humerus, the infraspinatus, with its insertion at the greater
tubercle of the humerus, and the teres minor, with its insertion at the greater tubercle
of the humerus.
Circumduction of the arms - muscles includes pectoralis major, subscapularis,
coracobrachialis, biceps brachii, supraspinatus, deltoid, latissimus dorsi, teres major
and minor, infraspinatus, long head of triceps.√ As the circumduction is a continuous
sequence of the above movements the practically all the above muscles are involved.
9.5/10
2. What are EPSPs and IPSPs, and how are they produced? Explain how these electrical
currents are used in spatial and temporal summation to initiate or inhibit the generation of
an action potential.
EPSPs means Excitatory and Inhibitory ? Postsynaptic Potentials while IPSPs means
Inhibitory Postsynaptic Potential (IPSP).
A neurotransmitter causes either an excitatory or an inhibitory graded potential. A
neurotransmitter that causes depolarization of the postsynaptic membrane is excitatory
because it brings the membrane closer to threshold√. Excitatory neurotransmitters cause an
opening of the ligand-gated sodium ion channels. As a result, Na+ ions influx and the cell
becomes negative on the inside (depolarization). When the depolarization crosses certain
threshold, neuron fires action potential.
A neurotransmitter that causes hyperpolarization of the post- synaptic membrane is
inhibitory√. During hyperpolarization, generation of an action potential is more difficult than
usual because the membrane potential becomes inside more negative and thus even farther
from threshold √ than in its resting state. When an inhibitory neurotransmitter activates the
receptor site, it causes additional K+ channels to open which may cause k+ ions to flow out
of the cell. This makes the inside of the cell to become negative. Inhibitory neurotransmitter
can also open a ligand-gated Cl- ion channels causing influx of chloride ions which causes
further hyperpolarization.
Whether a neuron generates an action potential or not, it all balls down to the overall sum of
EPSP’s and IPSP’s occurring at the neuron at any given time. Therefore, it is the summation
Assignment 2 :: Biology 235: Human Anatomy and Physiology 3
Answers to assignment questions must be original; that is, you must write them all yourself. You can base your answers
on information in the course textbook or other sources, but if you use sources other than the textbook, you must cite
them appropriately.
Plagiarism is a form of academic misconduct that has serious consequences. It is your responsibility to read and
understand the statement on Academic Integrity in the Student Manual and the Student Academic Misconduct Policy in
the AU undergraduate Calendar. If plagiarism is detected, and if an investigation concludes that you must rewrite the
assignment, then your assignment grade will be reduced by 20 marks.
“By filling in my name and ID number below, I acknowledge my responsibility to academic integrity and confirm that
none of the wording in my answers has been copied or plagiarized in any way from any source.”
Student’s name: BLESSING ADU
Student's AU ID number: 3450031
NOTE: The assignment will not be marked if it is submitted without the above two lines filled in.
BIOL 235
Assignment 2 :: Biology 235: Human Anatomy and Physiology 1
,Assignment 2
Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
Total mark = 93.5%
1. Name the type of joint, and list the movements permitted at the shoulder joint. Under each
movement’s name, list the names of the muscles responsible for each of these movements
along with descriptions of their bone insertion.
A joint is also known as articulation or arthrosis. It is a point of contact between two bones,
between bone and cartilage, or between bone and teeth. The types of joint includes fibrous
(immovable), Cartilaginous (partially moveable) and the Synovial (freely moveable) joint.
The shoulder joint also known as the humeroscapular joint, is a synovial ball-and-socket
joint formed by the head of the humerus and the glenoid cavity of the scapula. This joint
allows abduction, adduction, flexion, extension, hyperextension, medial rotation, lateral
rotation and, circumduction of the arm. The muscles responsible for each movement are
discussed below;
Abduction√ of the arm- the muscle includes the lateral fibers of the deltoid, with its
insertion at the deltoid tuberosity of the humerus, and the supraspinatus, with its
insertion at the greater tubercle of the humerus.√
Adduction √of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the teres
major with its insertion at the medial lip of the intertubercular sulcus of the humerus,
the latissimus dorsi, with its insertion at the intertubercular sulcus of the humerus,
and the coracobrachialis, with its insertion at the middle of the medial surface of the
shaft of the humerus.
Flexion of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the deltoid,
with its insertion at the deltoid tuberosity of the humerus, the coracobrachialis, with
its insertion at the middle of the medial surface of the shaft of the humerus, and the
biceps brachii, with its insertion at the radial tuberosity of radius and bicipital
aponeurosis.√
Extension of the arm- muscle includes the pectorial major, with its insertion at the
greater tubercle and lateral lip of intertubercular sulcus of the humerus, the
latissimus dorsi, with its insertion at the intertubercular sulcus of the humerus, the
deltoid, with its insertion at the deltoid tuberosity of the humerus, the
coracobrachialis, the teres major, with its insertion at the medial lip of the
Assignment 2 :: Biology 235: Human Anatomy and Physiology 2
, intertubercular sulcus of the humerus, and the teres minor, with its insertion at the
greater tubercle of the humerus.√
Medial rotation of the arm – the muscles includes the pectorial major, with its
insertion at the greater tubercle and lateral lip of intertubercular sulcus of the
humerus, the latissimus dorsi, with its insertion at the intertubercular sulcus of the
humerus, the deltoid, with its insertion at the deltoid tuberosity of the humerus, the
subscapularis, with its insertion at the lesser tubercle of humerus, and the teres
major, with its insertion at the medial lip of the intertubercular sulcus of the
humerus.√
Lateral rotation of the arm- the muscles include the deltoid, with its insertion at the
deltoid tuberosity of the humerus, the infraspinatus, with its insertion at the greater
tubercle of the humerus, and the teres minor, with its insertion at the greater tubercle
of the humerus.
Circumduction of the arms - muscles includes pectoralis major, subscapularis,
coracobrachialis, biceps brachii, supraspinatus, deltoid, latissimus dorsi, teres major
and minor, infraspinatus, long head of triceps.√ As the circumduction is a continuous
sequence of the above movements the practically all the above muscles are involved.
9.5/10
2. What are EPSPs and IPSPs, and how are they produced? Explain how these electrical
currents are used in spatial and temporal summation to initiate or inhibit the generation of
an action potential.
EPSPs means Excitatory and Inhibitory ? Postsynaptic Potentials while IPSPs means
Inhibitory Postsynaptic Potential (IPSP).
A neurotransmitter causes either an excitatory or an inhibitory graded potential. A
neurotransmitter that causes depolarization of the postsynaptic membrane is excitatory
because it brings the membrane closer to threshold√. Excitatory neurotransmitters cause an
opening of the ligand-gated sodium ion channels. As a result, Na+ ions influx and the cell
becomes negative on the inside (depolarization). When the depolarization crosses certain
threshold, neuron fires action potential.
A neurotransmitter that causes hyperpolarization of the post- synaptic membrane is
inhibitory√. During hyperpolarization, generation of an action potential is more difficult than
usual because the membrane potential becomes inside more negative and thus even farther
from threshold √ than in its resting state. When an inhibitory neurotransmitter activates the
receptor site, it causes additional K+ channels to open which may cause k+ ions to flow out
of the cell. This makes the inside of the cell to become negative. Inhibitory neurotransmitter
can also open a ligand-gated Cl- ion channels causing influx of chloride ions which causes
further hyperpolarization.
Whether a neuron generates an action potential or not, it all balls down to the overall sum of
EPSP’s and IPSP’s occurring at the neuron at any given time. Therefore, it is the summation
Assignment 2 :: Biology 235: Human Anatomy and Physiology 3
