Bio 1011 Animal Biology Flashcards
What are the characteristics of of an animal?
heterotrophic, multi-cellular, lacking a cell wall, capable of movement at some stage, has regulatory (hox) genes, reproduce and develop, obtain and transfer energy and matter, gas exchange, protection from external environment, maintenance of water and extra solutes
What are the 4 different types of tissues?
- Epithelial tissue: sheets of cells that cover organs and the body, acting as a barrier to mechanical and or chemical pathogens.
- Connective tissue: sparse collection of cells throughout extracellular matrix. Generally as a web of fibres in a liquid, jelly, or solid foundation. Contains fibroblasts that secrete fibre proteins, and macrophages that engulf foreign particles. 3 kinds in many different areas.
- Muscle Tissue: responsible for almost every type of movement in the human body via the action of actin and myosin. There is cardiac, smooth, and skeletal muscle tissue.
- Nervous Tissue: receive, transmit, and process information from stimuli. Consists of neurons and glia that make up a brain (processing centre) and long extensions to collect info.
Explain the structure of epithelial tissue in terms of polarity.
Epithelial tissue is polarized meaning it has 2 sides: apical faces the lumen, and basal faces inward.
What are some examples of connective tissue?
- Bone: bone-forming cells are called osteoblasts which create a matrix of collagen. Calcium, Mg, and phosphate ions exist in the matrix. The unit cell for bone is the osteon.
- Blood: liquid matrix called plasma with water, salts, and proteins. In addition, erythrocytes (red blood cells), leukocytes exist (white blood cells), and platelets (cell fragments involved in clotting) exist inside.
- Adipose tissue: loose connective tissue storing fat in adipose cells that pad an insulate the body.
- Cartilage: collagen fibres in a protein-carbohydrate complex. Its strong but also flexible, common in embryos before replaced by bone.
What is a functional trade-off?
When the specialization for one function limits the ability to preform another function as well or at all (example skin is semi-permeable to loose water but then is not as protective).
Explain how hierarchy in a system can show effects in 2 directions (i.e., small can affect larger system but larger system can also affect small).
If there is a problem with a biological system it can show effects on the smallest units: cells, as well as organs within. (Ex: problem with the brain shows problems in all cells)
But a problem with a single part can also affect the overall system/organism. (Ex: knee injury affects musculoskeletal system when other muscles need to compensate leading to overall locomotion problems).
What is an emergent property?
A property determining the overall function
- Ex: a cell is an emergent property of life, an eye is an emergent property of sensing light.
- Non-Ex: a nose is not an emergent property of smell, nose receptors are.
What is interstitial fluid?
The fluid that inhabits the space between cells.
What is negative feedback and what is its relationship to homeostasis?
A control mechanism that responds opposite to the stimulus, to return to the baseline body level and maintain homeostasis (reduces the disturbance).
Involves a stimulus, a sensor (perceiving the stimulus), and a control centre that determines how to respond and initiate.
What is positive feedback?
A control mechanism that reinforces the original stimulus; not aiming to maintain homeostasis, but to drive something ti competition. Ex: birth.
What are examples of homeostatic set points that change in the body over time?
- Puberty and menopause (hormone levels)
- Cyclic cycles like circadian rhythms and menstrual cycle.
- Acclimatization (responding to environmental changes, more than just 1)
- Acclimation (responding to 1 environmental change).
What is a resource trade-off?
When natural selection favours efficiency of resources, leading to trade offs between resources and energy.
Ex: Seals don’t digest their fish until above surface, so more oxygen can be provided to brain, heart, and locomotive processes.
What is a model organism? What is the one used for in fertilization research? In morphogenesis research?
An organism that can easily be studied for a particular process that is representative for a wide range of species.
In fertilization, the sea urchin is used.
In morphogenesis and cleavage: frog.
What is the acrosomal reaction?
When the hydrolytic enzymes released from the acrosome on a sperm eat through the jelly layer or the egg. The acrosomal process then forms from the actin filaments of the sperm, which penetrates the jelly coat and its proteins bind to the sperm receptors on the egg’s plasma membrane.
What are the 2 ways polyspermy is prevented in fertilization?
- Fast block: once the sperm is bound to the receptors on the egg, the two nuclei fuse. This allows the sodium channels to open up in the egg, depolarizing it, and creating an approx. 1 minute block.
- Slow block: the cortical reaction: the granules in the egg fuse with the eggs plasma membrane (in between the vitelline layer called the perivitelline space). This removes the sperm receptors, and hardens the vitelline layer to form a fertilization envelope.
What is “egg activation” and what is necessary for it to occur.
Calcium ions initiate the cortical reaction, or the activation of the egg, in which the fertilization envelope is formed.
What is the rapid cell divisoo stage following fertilization?
Cleavage: rapid cell divisions that skip the G1 and G2 phase of the cell cycle, essentially creating a mass of cell the same size as the initial zygote. These cells are called blastomere or a blastula cell. The collection of cells has a hollow fluid-filled interior known as the blastocoel.
What are the 2 poles of the blastula?
Vegetal pole and animal pole, which describes the distribution of stored nutrients or “yolk”.
Vegetal pole: more yolk concentration
Animal pole: opposite pole, less concentration.
These poles then differ in appearance because of this.
What are the 2 main factors that contribute to different looking or different structured cells?
Gene expression is responsible, and does this in 2 main ways:
- Cytoplasmic determinants: molecules in cytoplasm that regulate gene expression. The determinants in each cell are determined by cleavage and which pole the cell was in, and of course further replications.
- Inductive signalling: Signals the cell is exposed to, depends on location of cell in the embryo and the stage of development.
What are the 3 germ layers and at what stage are they developed?
The reorganization of the hollow blastocoel in gastrulation creates the 3 germ layers:
- Ectoderm (outer): blue
- Mesoderm (middle): red
- Endoderm (inner): yellow, lines the digestive tract
What process forms the preliminary digestive tract and what is the preliminary version called?
The invagination of the blastocoel wall on the vegetal pole creates a deeper, narrow tube called the archenteron. This tube will form the digestive tract, with the open end forming the anus which is called the blastopore.
In this process the blastocoel disappears.
What are the 2 processes of morphogenesis?
- Gastrulation: rearrangement of the cells in the blastocoel, creating the 3 germ layers and the archenteron.
- Organogenesis: formation of organs, beginning with neurulation.
What is convergent extension and what is one of its applications?
The rearrangement of cells in a sheet that become narrower (converge) and longer (extend). This process is used in neurulation.
Explain the process of neurulation.
The neural plate develops from ectoderm tissue, that sits above the notochord. It begins the neural fold, eventually completely pinching to first form the neural crest (connecting the soon to be neural tube and the outer ectoderm that pinched in) and second become the neural tube.
The neural tube then sits above the notochord, covered in ectoderm tissue with a bump where the neural tube/spine exists.
What are the 2 main organs responsible for regulating the endocrine system?
- The hypothalamus (nervous tissue)
2. Pituitary gland (endocrine cells) which is beside the hypothalamus
Explain the interaction between the pituitary gland and the hypothalamus
The posterior pit. gland is made up of axons of neurosecretory cells from the hypothalamus, in which release hormones directly into the blood.
The anterior pit. gland is endocrine cells that respond to hormones from the hypothalamus via portal vessels. The hormones control what hormones are subsequently released.
From there, these hormones released from pituitary gland control hormones released in other glands.
Explain the fight of flight response in terms of the hypothalamus and endocrine system.
Stress arrives at the hypothalamus which causes a nerve impulse down the spinal cord to the adrenal medulla, which secretes epinephrine and norepinephrine.
Explain how water-insoluble hormones and water-insoluble hormones differ in their pathways.
Water soluble cells require release from cell by a vesicle as they can’t pass over the lipid bilayer. However, they can freely pass into the blood stream and out. They require a receptor on the surface of the cell, meaning they must go through signal transduction before creating gene expression/activity.
Water-insoluble on the other hand don’t require a vesicle to pass out of the cell, but they require a transport protein while passing though the blood. When they reach the target cell they can pass through and go right to the nucleus for gene expression (no transduction needed usually).
Why do hormones show different responses in target cells?
- The type of receptor it binds to. Each receptor only has one specific hormone, but a hormone may have different types of receptors (i.e., alpha and beta form).
- The signalling pathway/proteins within the cell (ex. a receptor in different cells in the body will show different results: in liver norepinephrine receptor will release glucose as a response, in skeletal-vessel area the response will be vessel dilation for the same signal and receptor).
What is an antagonistic hormone?
A pair of hormones that have opposing functions/responses.
Describe the role of insulin and glucagon in the cell.
Insulin is released by beta cells in the pancreas when blood glucose is high, it causes glucose to be stored in the liver.
Glucagon is produced by alpha cells in the pancreas when blood glucose is low, it causes the liver to convert the stored glycogen to be converted to glucose and travel into the blood.
You can see here how these two can be a combined loop of events.
In general, how does the nervous system send signals throughout the body?
They send signals via electrical impulses. These impulses are very fast, much faster that endocrine, and the duration is short (typically external stimuli from immediate stimuli).
Neurotransmitters are also involved, brining a chemical aspect of signalling.
In general, how does the endocrine system send signals throughout the body?
Through hormones that travel; through the blood to target cells. This process can vary in speed and duration, but is specialized for gradual changes over the body and affecting a larger portion (than electrical), if not the whole, body.
What are glial cells?
Cells in the nervous system that help maintain homeostasis, by creating myelin (fatty substance covering the axons of neurons) to protect and support cells in the CNS and PNS.
What composes the CNS? The PNS?
CNS=brain and spinal cord
PNS=cranial nerves, spinal nerves, ganglia of cells outside of CNS (bundles of nerves from CNS)
What are the 3 stages of information processing in the nervous system?
- Sensory input (in PNS)
- Integration (CNS)
- Output (e.g., motor function) (CNS)
Explain how the motor, sensory, and inter-neuron interact when sending an electrical signal.
The stimuli activates the sensory neuron, travelling to the spinal card for processing. From there the impulse goes 2 ways: to the motor neuron for direct response (faster) and to the brain via an interneuron for complete processing of the stimulus (slower).
This explains why reaction can be a lot faster than understanding, ex: putting hand on hot surface.
Compare BMR to metabolic rate.
Metabolic rate is the energy used by an animal/time.
BMR is energy used/time when on an empty stomach, no stress, and for an endotherm.
Explain the relationship between BMR and Mass.
BMR increases with mass, however, the larger the animal the more efficient they are with their energy use (if based on energy used/unit mass on that animal larger animals will have lower).
BMR=mass^(3/4)
4 ways that you can measure an animals energy usage?
- O2 consumption
- Co2 production
- Food consump. + waste elim.
- Heat production (metabolism)
