Human Biology

Question 1

Define and briefly describe the process of “Homeostasis”?

Answer 1

an organism’s ability to maintain a relatively stable internal environment

internal or external changes cause the internal environment to become imbalanced, so self-regulatory mechanisms are employed to return to a normal state

Question 2

Name 3 variables that are controlled by homeostasis

Answer 2

Chemically signalling molecules
core body temperature
ion concentration

Question 3

What is a “negative feedback loop”?

Answer 3

the primary homeostatic control mechanism in the body, where the final response aims to remove or oppose the initial signal

e.g. temp regulation - shiver to generate heat = body returns to set point = signal of low body temp is removed

Question 4

What is a “positive feedback loop”?

Answer 4

The end response continually reinforces the stimulus and therefore the response becomes amplified until an external intervention breaks the loop

e.g. contraction during childbirth only ceases after the baby is born and the cervix is no longer being stretched

Question 5

Describe the structure of the human respiratory system

Answer 5

Question 6

Describe the process of “Inhalation”

Answer 6

The diaphragm contracts downwards and the lungs expand upwards

the increase in volume in the lungs creates a low-pressure environment, which sucks air in like a vacuum

Question 7

Describe the process of “exhalation”

Answer 7

the diaphragm relaxes upwards and the lungs shrink to their original size

there’s a decrease in volume in the lungs which creates a high-pressure environment that pushes air out

Question 8

Describe the process of “gas exchange” in the respiratory system

Answer 8

alveoli are high in oxygen vs blood low in oxygen = diffuse of oxygen across the capillary bed

simultaneously, carbon dioxide diffuses out of the capillary - going from high conc. in blood to low conc. in alveoli

Question 9

Describe the structure of the heart

Answer 9

Question 10

What are the two different types of circulation?

Answer 10

Pulmonary - deoxygenated blood is carried from the heart to the lungs for gas exchange

Systemic - oxygenated blood is carried from the heart to the rest of the body

Question 11

What is the function of veins?

Answer 11

transportation of blood towards the heart

Question 12

What is the function of arteries?

Answer 12

transportation of blood, under high pressure, away from the heart

Question 13

What is the function of capillaries?

Answer 13

connect cellular structures and enable more targeted access to blood to supply cells with necessary molecules

Question 14

Describe the circulation of blood within the heart

Answer 14

right and left atrium of the heart collects blood from the superior/inferior vena cave and pulmonary vein respectively

blood moves into their respective right and left ventricles, and exits the heart into the pulmonary artery and aorta respectively

Question 15

What is the function of the “mouth” in the digestive system?

Answer 15

Mechanical and chemical breakdown of food via salivary amylase and teeth

Food is formed into bolus, then swallowed

Question 16

What is the function of the “oesophagus” in the digestive system?

Answer 16

constricts in a circular pattern, passing bolus into stomach

Question 17

What is the function of the “stomach” in the digestive system?

Answer 17

Mechanically (contraction of stomach muscle) and chemically (gastric acid) breaks down

Question 18

What is the function of the “duodenum” in the digestive system?

Answer 18

bolus mixed with digestive enzymes and bile salts secreted from the pancreas and liver respectively

Question 19

What is the function of the “jejunum” in the digestive system?

Answer 19

villi aids in the absorption of nutrients from the lumen into the bloodstream

Question 20

What is the function of the “ileum” in the digestive system?

Answer 20

absorbs vitamin B12, bile salts and any products of digestion that where not absorbed by jejunum

Question 21

What is the function of the “liver” & “gallbladder” in the digestive system?

Answer 21

liver produces bile salts that can be stored in the gallbladder and secreted into the duodenum to aid in fat absorption

liver also filters and breaks down toxins in the body

Question 22

What is the function of the “pancreas” in the digestive system?

Answer 22

produces digestive enzymes which are secreted into the duodenum

produces hormones such as insulin and glucagon

Question 23

What are the two components that make up the digestive system?

Answer 23

Gastrointestinal tract
accessory organs

Question 24

What are hormones?

Answer 24

molecules released by cells in endocrine glands that act as messengers in the body., influencing structure or metabolic rate

Question 25

Name 3 different types of hormonal signalling

Answer 25

Question 26

What is the purpose of the HPA axis?

Answer 26

responsible for maintaining corticosteroid release hypothalamus senses when blood corticosteroid conc. is low and secretes CRH CRH stimulates the pituitary gland to secrete ACTH ACTH travels via the blood to the adrenal gland, stimulating more glucocorticoids until levels return to baseline, inhibiting CRH and ACTH

Question 27

What is the purpose of the oxytocin loop during childbirth?

Answer 27

Question 28

Define the role and response of The Innate Immune System

Answer 28

provides the first line of defence against pathogens or foreign bodies the response is rapid, but non-specific and remains the same every time, only vary depending on the pathogen that invades the body

Question 29

Define the role and response of The Adaptive Immune System

Answer 29

response is slower but targeted to a specific type of pathogen the slower response allows the development of immunological memory should the pathogen be encountered again

Question 30

What does the Primary Immune System consist of?

Answer 30

Bone Marrow - site of B & T cell development and maturation Thymus - site of T cell maturation

Question 31

What does the Secondary Immune System consist of?

Answer 31

Lymph-nodes - central site for immune cells and help filter circulating lymph to fight infections Spleen - an organ responsible for surveillance and removal of dead RBC and also produces blood cells in the fetus Peyer's Patches - facilitates adaptive immunity in the mucosal surfaces of the gut

Question 32

What are the 5 major bone groups?

Answer 32

Question 33

What is the purpose of cartilage?

Answer 33

a connective tissue that lines the surface of bones to allow movement and protect against impact

Question 34

What are the 3 major types of muscles?

Answer 34

Skeletal Muscle, makes up the musculoskeletal system Smooth Muscle, found on the lining of hollow organs Cardiac Muscle, makes up the heart

Question 35

What is the difference between tendons and ligaments?

Answer 35

Tendons - connects muscle to bone, very rigid Ligaments - connects bone to bone, more flexible

Question 36

What is a nerve and what is its function?

Answer 36

Bundles of neurons that connect our sensory receptors to our brains, and connect our brains to our motor areas, via action potential

Question 37

What is an action potential?

Answer 37

biochemical mechanisms by which neurons send messages

Question 38

Describe the pathway of an action potential

Answer 38

Dendrites receive a signal that triggers action potential and passes through to the cell body, which hosts the nucleus Travels down through Axon, continuing to the Axon Terminal A Synapse forms with whatever the neuron is trying to signal to

Question 39

What is the structure and role of the central nervous system?

Answer 39

nerves in the brain and spinal cord recieve all the info from the PNS and regulate the body, process thought and store memories

Question 40

What is the structure and role of the Peripheral nervous system?

Answer 40

includes the sensory neurons and motor neurons these nerves connect with the nerves in the spinal cord so that signals can be sent from the PNS to the CNS and vice versa

Question 41

What are the two sub-groups of the PNS?

Answer 41

Somatic Nervous System - the sensory and motor system Autonomic Nervous System - the system that controls things you are not conscious of

Question 42

What is the function of the kidneys?

Answer 42

essential in maintaining homeostasis of the human body, predominantly through its main role - filtering blood

Question 43

What role does the Nephron play in the kidneys?

Answer 43

main role is to filter blood to remove toxins and waste and maintain homeostasis for the rest of the body responsible for collecting filtrate which will become urine which can leave the kidney and allow waste to be removed from the body