Human Biology Flashcards
Homeostasis, Respiratory System, Circulatory System, Digestive System, Endocrine System, Immune System, Musculosketal System, Nervous System & Renal System
Define and briefly describe the process of “Homeostasis”?
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
Name 3 variables that are controlled by homeostasis
Chemically signalling molecules
core body temperature
ion concentration
What is a “negative feedback loop”?
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
What is a “positive feedback loop”?
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
Describe the structure of the human respiratory system
Describe the process of “Inhalation”
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
Describe the process of “exhalation”
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
Describe the process of “gas exchange” in the respiratory system
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
Describe the structure of the heart
What are the two different types of circulation?
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
What is the function of veins?
transportation of blood towards the heart
What is the function of arteries?
transportation of blood, under high pressure, away from the heart
What is the function of capillaries?
connect cellular structures and enable more targeted access to blood to supply cells with necessary molecules
Describe the circulation of blood within the heart
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
What is the function of the “mouth” in the digestive system?
Mechanical and chemical breakdown of food via salivary amylase and teeth
Food is formed into bolus, then swallowed
What is the function of the “oesophagus” in the digestive system?
constricts in a circular pattern, passing bolus into stomach
What is the function of the “stomach” in the digestive system?
Mechanically (contraction of stomach muscle) and chemically (gastric acid) breaks down
What is the function of the “duodenum” in the digestive system?
bolus mixed with digestive enzymes and bile salts secreted from the pancreas and liver respectively
What is the function of the “jejunum” in the digestive system?
villi aids in the absorption of nutrients from the lumen into the bloodstream
What is the function of the “ileum” in the digestive system?
absorbs vitamin B12, bile salts and any products of digestion that where not absorbed by jejunum
What is the function of the “liver” & “gallbladder” in the digestive system?
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
What is the function of the “pancreas” in the digestive system?
produces digestive enzymes which are secreted into the duodenum
produces hormones such as insulin and glucagon
What are the two components that make up the digestive system?
Gastrointestinal tract
accessory organs
What are hormones?
molecules released by cells in endocrine glands that act as messengers in the body., influencing structure or metabolic rate
Name 3 different types of hormonal signalling
What is the purpose of the HPA axis?
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
What is the purpose of the oxytocin loop during childbirth?
Define the role and response of The Innate Immune System
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
Define the role and response of The Adaptive Immune System
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
What does the Primary Immune System consist of?
Bone Marrow - site of B & T cell development and maturation
Thymus - site of T cell maturation
What does the Secondary Immune System consist of?
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
What are the 5 major bone groups?
What is the purpose of cartilage?
a connective tissue that lines the surface of bones to allow movement and protect against impact
What are the 3 major types of muscles?
Skeletal Muscle, makes up the musculoskeletal system
Smooth Muscle, found on the lining of hollow organs
Cardiac Muscle, makes up the heart
What is the difference between tendons and ligaments?
Tendons - connects muscle to bone, very rigid
Ligaments - connects bone to bone, more flexible
What is a nerve and what is its function?
Bundles of neurons that connect our sensory receptors to our brains, and connect our brains to our motor areas, via action potential
What is an action potential?
biochemical mechanisms by which neurons send messages
Describe the pathway of an action potential
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
What is the structure and role of the central nervous system?
nerves in the brain and spinal cord
recieve all the info from the PNS and regulate the body, process thought and store memories
What is the structure and role of the Peripheral nervous system?
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
What are the two sub-groups of the PNS?
Somatic Nervous System - the sensory and motor system
Autonomic Nervous System - the system that controls things you are not conscious of
What is the function of the kidneys?
essential in maintaining homeostasis of the human body, predominantly through its main role - filtering blood
What role does the Nephron play in the kidneys?
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
